Merge branch 'dev' into remove_posix_tz_parser

tests/component_tests/binary_sensor/test_binary_sensor.py

@@ -1,5 +1,7 @@
 """Tests for the binary sensor component."""
 
+from tests.component_tests.helpers import INTERNAL_BIT, extract_packed_value
+
 
 def test_binary_sensor_is_setup(generate_main):
     """
@@ -29,7 +31,7 @@ def test_binary_sensor_sets_mandatory_fields(generate_main):
     )
 
     # Then
-    assert 'bs_1->set_name("test bs1",' in main_cpp
+    assert 'bs_1->configure_entity_("test bs1",' in main_cpp
     assert "bs_1->set_pin(" in main_cpp
 
 
@@ -44,9 +46,9 @@ def test_binary_sensor_config_value_internal_set(generate_main):
         "tests/component_tests/binary_sensor/test_binary_sensor.yaml"
     )
 
-    # Then
-    assert "bs_1->set_internal(true);" in main_cpp
-    assert "bs_2->set_internal(false);" in main_cpp
+    # Then: bs_1 has internal: true, bs_2 has internal: false
+    assert extract_packed_value(main_cpp, "bs_1") & INTERNAL_BIT != 0
+    assert extract_packed_value(main_cpp, "bs_2") & INTERNAL_BIT == 0
 
 
 def test_binary_sensor_config_value_use_raw_set(generate_main):

tests/component_tests/button/test_button.py

@@ -1,5 +1,7 @@
 """Tests for the button component"""
 
+from tests.component_tests.helpers import INTERNAL_BIT, extract_packed_value
+
 
 def test_button_is_setup(generate_main):
     """
@@ -26,7 +28,7 @@ def test_button_sets_mandatory_fields(generate_main):
     main_cpp = generate_main("tests/component_tests/button/test_button.yaml")
 
     # Then
-    assert 'wol_1->set_name("wol_test_1",' in main_cpp
+    assert 'wol_1->configure_entity_("wol_test_1",' in main_cpp
     assert "wol_2->set_macaddr(18, 52, 86, 120, 144, 171);" in main_cpp
 
 
@@ -39,6 +41,6 @@ def test_button_config_value_internal_set(generate_main):
     # When
     main_cpp = generate_main("tests/component_tests/button/test_button.yaml")
 
-    # Then
-    assert "wol_1->set_internal(true);" in main_cpp
-    assert "wol_2->set_internal(false);" in main_cpp
+    # Then: wol_1 has internal: true, wol_2 has internal: false
+    assert extract_packed_value(main_cpp, "wol_1") & INTERNAL_BIT != 0
+    assert extract_packed_value(main_cpp, "wol_2") & INTERNAL_BIT == 0

tests/component_tests/helpers.py

@@ -0,0 +1,19 @@
+"""Shared helpers for component tests."""
+
+from __future__ import annotations
+
+import re
+
+INTERNAL_BIT = 1 << 24
+
+
+def extract_packed_value(main_cpp: str, var_name: str) -> int:
+    """Extract the third (packed) argument from a configure_entity_ call."""
+    pattern = (
+        rf"{re.escape(var_name)}->configure_entity_\("
+        r'"(?:\\.|[^"\\])*"'
+        r",\s*\w+,\s*(\d+)\)"
+    )
+    match = re.search(pattern, main_cpp)
+    assert match, f"configure_entity_ call not found for {var_name}"
+    return int(match.group(1))

tests/component_tests/logger/test_logger.py

@@ -0,0 +1,50 @@
+"""Tests for the logger component."""
+
+import re
+
+
+def test_logger_pre_setup_before_other_components(generate_main):
+    """Logger::pre_setup() must be called before any other component is created.
+
+    Log functions call global_logger->log_vprintf_() without a null check,
+    so global_logger must be set before anything can log.
+    """
+    main_cpp = generate_main("tests/component_tests/logger/test_logger.yaml")
+
+    # Find the logger's pre_setup() call specifically
+    logger_pre_setup = re.search(r"logger_logger->pre_setup\(\)", main_cpp)
+    if logger_pre_setup is None:
+        # Fall back to finding any logger-related pre_setup
+        logger_pre_setup = re.search(r"logger\w*->pre_setup\(\)", main_cpp)
+    assert logger_pre_setup is not None, (
+        "Logger pre_setup() not found in generated code"
+    )
+
+    # Find all "new " allocations (component creation)
+    new_allocations = list(re.finditer(r"\bnew [\w:]+", main_cpp))
+    assert len(new_allocations) > 0, "No component allocations found"
+
+    # Separate logger and non-logger allocations
+    logger_allocs = [a for a in new_allocations if "logger" in a.group().lower()]
+    non_logger_allocs = [
+        a
+        for a in new_allocations
+        if "logger" not in a.group().lower()
+        # Skip placement new for App
+        and "(&App)" not in main_cpp[max(0, a.start() - 5) : a.start()]
+    ]
+
+    assert len(logger_allocs) > 0, (
+        f"Logger allocation not found in: {[a.group() for a in new_allocations]}"
+    )
+    assert len(non_logger_allocs) > 0, (
+        "No non-logger component allocations found — "
+        "add a component to test_logger.yaml so the ordering check is meaningful"
+    )
+
+    # All non-logger allocations must appear after logger pre_setup()
+    for alloc in non_logger_allocs:
+        assert alloc.start() > logger_pre_setup.start(), (
+            f"Component allocation '{alloc.group()}' at position {alloc.start()} "
+            f"appears before logger pre_setup() at position {logger_pre_setup.start()}"
+        )

tests/component_tests/logger/test_logger.yaml

@@ -0,0 +1,14 @@
+---
+esphome:
+  name: test
+
+esp8266:
+  board: d1_mini_lite
+
+logger:
+  level: DEBUG
+
+# Need at least one non-logger component so the ordering test
+# can verify that logger pre_setup() comes before other allocations.
+preferences:
+  flash_write_interval: 1min

tests/component_tests/sensor/test_sensor.py

@@ -1,5 +1,7 @@
 """Tests for the sensor component."""
 
+from tests.component_tests.helpers import extract_packed_value
+
 
 def test_sensor_device_class_set(generate_main):
     """
@@ -10,5 +12,6 @@ def test_sensor_device_class_set(generate_main):
     # When
     main_cpp = generate_main("tests/component_tests/sensor/test_sensor.yaml")
 
-    # Then
-    assert 's_1->set_device_class("voltage");' in main_cpp
+    # Then: device_class: voltage means packed value must be non-zero
+    packed = extract_packed_value(main_cpp, "s_1")
+    assert packed != 0

tests/component_tests/text/test_text.py

@@ -1,4 +1,6 @@
-"""Tests for the binary sensor component."""
+"""Tests for the text component."""
+
+from tests.component_tests.helpers import INTERNAL_BIT, extract_packed_value
 
 
 def test_text_is_setup(generate_main):
@@ -25,7 +27,7 @@ def test_text_sets_mandatory_fields(generate_main):
     main_cpp = generate_main("tests/component_tests/text/test_text.yaml")
 
     # Then
-    assert 'it_1->set_name("test 1 text",' in main_cpp
+    assert 'it_1->configure_entity_("test 1 text",' in main_cpp
 
 
 def test_text_config_value_internal_set(generate_main):
@@ -37,9 +39,9 @@ def test_text_config_value_internal_set(generate_main):
     # When
     main_cpp = generate_main("tests/component_tests/text/test_text.yaml")
 
-    # Then
-    assert "it_2->set_internal(false);" in main_cpp
-    assert "it_3->set_internal(true);" in main_cpp
+    # Then: it_2 has internal: false, it_3 has internal: true
+    assert extract_packed_value(main_cpp, "it_2") & INTERNAL_BIT == 0
+    assert extract_packed_value(main_cpp, "it_3") & INTERNAL_BIT != 0
 
 
 def test_text_config_value_mode_set(generate_main):
@@ -66,5 +68,20 @@ def test_text_config_lamda_is_set(generate_main):
     main_cpp = generate_main("tests/component_tests/text/test_text.yaml")
 
     # Then
-    assert "it_4->set_template([]() -> esphome::optional<std::string> {" in main_cpp
+    assert "it_4->set_template([]() -> std::optional<std::string> {" in main_cpp
     assert 'return std::string{"Hello"};' in main_cpp
+
+
+def test_esphome_optional_alias_works(generate_main):
+    """
+    Test that esphome::optional alias compiles (backward compatibility)
+    """
+    # Given
+
+    # When
+    main_cpp = generate_main("tests/component_tests/text/test_text.yaml")
+
+    # Then
+    # Codegen emits std::optional, but esphome::optional must also work
+    # via the using alias in esphome/core/optional.h
+    assert "std::optional<std::string>" in main_cpp

tests/component_tests/text_sensor/test_text_sensor.py

@@ -1,5 +1,7 @@
 """Tests for the text sensor component."""
 
+from tests.component_tests.helpers import INTERNAL_BIT, extract_packed_value
+
 
 def test_text_sensor_is_setup(generate_main):
     """
@@ -25,9 +27,9 @@ def test_text_sensor_sets_mandatory_fields(generate_main):
     main_cpp = generate_main("tests/component_tests/text_sensor/test_text_sensor.yaml")
 
     # Then
-    assert 'ts_1->set_name("Template Text Sensor 1",' in main_cpp
-    assert 'ts_2->set_name("Template Text Sensor 2",' in main_cpp
-    assert 'ts_3->set_name("Template Text Sensor 3",' in main_cpp
+    assert 'ts_1->configure_entity_("Template Text Sensor 1",' in main_cpp
+    assert 'ts_2->configure_entity_("Template Text Sensor 2",' in main_cpp
+    assert 'ts_3->configure_entity_("Template Text Sensor 3",' in main_cpp
 
 
 def test_text_sensor_config_value_internal_set(generate_main):
@@ -39,9 +41,9 @@ def test_text_sensor_config_value_internal_set(generate_main):
     # When
     main_cpp = generate_main("tests/component_tests/text_sensor/test_text_sensor.yaml")
 
-    # Then
-    assert "ts_2->set_internal(true);" in main_cpp
-    assert "ts_3->set_internal(false);" in main_cpp
+    # Then: ts_2 has internal: true, ts_3 has internal: false
+    assert extract_packed_value(main_cpp, "ts_2") & INTERNAL_BIT != 0
+    assert extract_packed_value(main_cpp, "ts_3") & INTERNAL_BIT == 0
 
 
 def test_text_sensor_device_class_set(generate_main):
@@ -53,6 +55,9 @@ def test_text_sensor_device_class_set(generate_main):
     # When
     main_cpp = generate_main("tests/component_tests/text_sensor/test_text_sensor.yaml")
 
-    # Then
-    assert 'ts_2->set_device_class("timestamp");' in main_cpp
-    assert 'ts_3->set_device_class("date");' in main_cpp
+    # Then: ts_2 has device_class: timestamp, ts_3 has device_class: date
+    # so their packed values must be non-zero
+    packed_ts_2 = extract_packed_value(main_cpp, "ts_2")
+    assert packed_ts_2 != 0
+    packed_ts_3 = extract_packed_value(main_cpp, "ts_3")
+    assert packed_ts_3 != 0

tests/components/README.md

@@ -7,10 +7,23 @@
 testing binaries that combine many components. By convention, this unique namespace is `esphome::component::testing`
 (where "component" is the component under test), for example: `esphome::uart::testing`.
 
+### Platform components
+
+For components that expose to a platform component, create a folder under your component test folder with the platform component name, e.g. `binary_sensor` and
+include the relevant `.cpp` and `.h` test files there.
+
+### Override component code generation for testing
+
+When generating code for testing, ESPHome won't invoke the component's `to_code` function, since most components do not
+need to generate configuration code for testing.
+
+If you do need to generate code to for example configure compilation flags or add libraries,
+add the component name to the `CPP_TESTING_CODEGEN_COMPONENTS` allowlist in `script/cpp_unit_test.py`.
 
 ## Running component unit tests
 
 (from the repository root)
+
 ```bash
 ./script/cpp_unit_test.py component1 component2 ...
 ```

tests/components/api/test.ln882x-ard.yaml

@@ -0,0 +1,5 @@
+<<: !include common.yaml
+
+wifi:
+  ssid: MySSID
+  password: password1

tests/components/audio_file/common.yaml

@@ -0,0 +1,9 @@
+audio_file:
+  - id: test_audio
+    file:
+      type: local
+      path: $component_dir/test.wav
+
+media_source:
+  - platform: audio_file
+    id: audio_file_source

tests/components/audio_file/test.esp32-idf.yaml

@@ -0,0 +1 @@
+<<: !include common.yaml

tests/components/ble_nus/test-uart.nrf52-adafruit.yaml

@@ -0,0 +1,4 @@
+ble_nus:
+  type: uart
+  tx_buffer_size: 160
+  rx_buffer_size: 160

tests/components/captive_portal/test.rp2040-ard.yaml

@@ -0,0 +1 @@
+<<: !include common.yaml

tests/components/dew_point/common.yaml

@@ -0,0 +1,19 @@
+sensor:
+  - platform: dew_point
+    name: Dew Point
+    temperature: template_temperature
+    humidity: template_humidity
+  - platform: template
+    id: template_humidity
+    lambda: |-
+      if (millis() > 10000) {
+        return 0.6;
+      }
+      return 0.0;
+  - platform: template
+    id: template_temperature
+    lambda: |-
+      if (millis() > 10000) {
+        return 42.0;
+      }
+      return 0.0;

tests/components/dew_point/test.esp32-idf.yaml

@@ -0,0 +1 @@
+<<: !include common.yaml

tests/components/dew_point/test.esp8266-ard.yaml

@@ -0,0 +1 @@
+<<: !include common.yaml

tests/components/dew_point/test.rp2040-ard.yaml

@@ -0,0 +1 @@
+<<: !include common.yaml

tests/components/esp8266/test.esp8266-ard.yaml

@@ -1,3 +1,6 @@
+esp8266:
+  enable_full_printf: false
+
 logger:
   level: VERBOSE
 

tests/components/external_components/common.yaml

@@ -1,6 +1,8 @@
 external_components:
-  - source: github://esphome/esphome@dev
+  - id: my_ext
+    source: github://esphome/esphome@dev
     refresh: 1d
     components: [bh1750]
-  - source: ../../../esphome/components
+  - id: my_local
+    source: ../../../esphome/components
     components: [sntp]

tests/components/external_components/test.esp32-idf.yaml

@@ -1 +1,5 @@
+# WARNING: Using !extend or !remove prevents automatic component grouping in CI, making builds slower.
 <<: !include common.yaml
+
+external_components:
+  - id: !remove my_local

tests/components/globals/common.yaml

@@ -27,3 +27,14 @@ globals:
     type: bool
     restore_value: false
     initial_value: "false"
+  # Test restore_value with string "false" - should be converted to bool false
+  - id: glob_no_restore_string_false
+    type: int
+    restore_value: "false"
+    initial_value: "42"
+  # Test restore_value with string "true" - should be converted to bool true
+  - id: glob_restore_string_true
+    type: int
+    restore_value: "true"
+    initial_value: "99"
+    update_interval: 5s

tests/components/http_request/test.esp8266-ard.yaml

@@ -1,4 +1,6 @@
-substitutions:
-  verify_ssl: "false"
-
 <<: !include common.yaml
+
+http_request:
+  verify_ssl: false
+  tls_buffer_size_rx: 16384
+  tls_buffer_size_tx: 512

tests/components/integration/common-esp32.yaml

@@ -1,9 +1,19 @@
+esphome:
+  on_boot:
+    then:
+      - sensor.integration.reset:
+          id: integration_sensor
+      - sensor.integration.set_value:
+          id: integration_sensor
+          value: 100.0
+
 sensor:
   - platform: adc
     id: my_sensor
     pin: ${pin}
     attenuation: 12db
   - platform: integration
+    id: integration_sensor
     sensor: my_sensor
     name: Integration Sensor
     time_unit: s

tests/components/ld2450/common.h

@@ -16,7 +16,7 @@ class MockUARTComponent : public uart::UARTComponent {
   MOCK_METHOD(bool, read_array, (uint8_t * data, size_t len), (override));
   MOCK_METHOD(bool, peek_byte, (uint8_t * data), (override));
   MOCK_METHOD(size_t, available, (), (override));
-  MOCK_METHOD(void, flush, (), (override));
+  MOCK_METHOD(uart::FlushResult, flush, (), (override));
   MOCK_METHOD(void, check_logger_conflict, (), (override));
 };
 

tests/components/main.cpp

@@ -1,5 +1,7 @@
 #include <gtest/gtest.h>
 
+#include "esphome/components/logger/logger.h"
+
 /*
 This special main.cpp replaces the default one.
 It will run all the Google Tests found in all compiled cpp files and then exit with the result
@@ -18,6 +20,12 @@ void original_setup() {
 }
 
 void setup() {
+  // Log functions call global_logger->log_vprintf_() without a null check,
+  // so we must set up a Logger before any test that triggers logging.
+  static esphome::logger::Logger test_logger(0);
+  test_logger.set_log_level(ESPHOME_LOG_LEVEL);
+  test_logger.pre_setup();
+
   ::testing::InitGoogleTest();
   int exit_code = RUN_ALL_TESTS();
   exit(exit_code);

tests/components/modbus/common.yaml

@@ -1,3 +1,5 @@
 modbus:
   id: mod_bus1
   flow_control_pin: ${flow_control_pin}
+  send_wait_time: 500ms
+  turnaround_time: 100ms

tests/components/nextion/common_tft_upload.yaml

@@ -0,0 +1,5 @@
+display:
+  - id: !extend main_lcd
+    tft_url: http://esphome.io/default35.tft
+    tft_upload_http_timeout: 20s
+    tft_upload_http_retries: 10

tests/components/nextion/common_tft_upload_watchdog.yaml

@@ -0,0 +1,3 @@
+display:
+  - id: !extend main_lcd
+    tft_upload_watchdog_timeout: 30s

tests/components/nextion/test.esp32-ard.yaml

@@ -1,7 +1,5 @@
 packages:
   uart: !include ../../test_build_components/common/uart/esp32-ard.yaml
   base: !include common.yaml
-
-display:
-  - id: !extend main_lcd
-    tft_url: http://esphome.io/default35.tft
+  tft_upload: !include common_tft_upload.yaml
+  tft_upload_watchdog: !include common_tft_upload_watchdog.yaml

tests/components/nextion/test.esp32-idf.yaml

@@ -1,7 +1,5 @@
 packages:
   uart: !include ../../test_build_components/common/uart/esp32-idf.yaml
   base: !include common.yaml
-
-display:
-  - id: !extend main_lcd
-    tft_url: http://esphome.io/default35.tft
+  tft_upload: !include common_tft_upload.yaml
+  tft_upload_watchdog: !include common_tft_upload_watchdog.yaml

tests/components/nextion/test.esp8266-ard.yaml

@@ -1,7 +1,4 @@
 packages:
   uart: !include ../../test_build_components/common/uart/esp8266-ard.yaml
   base: !include common.yaml
-
-display:
-  - id: !extend main_lcd
-    tft_url: http://esphome.io/default35.tft
+  tft_upload: !include common_tft_upload.yaml

tests/components/online_image/common.yaml

@@ -40,6 +40,10 @@ online_image:
     url: https://samples-files.com/samples/images/bmp/480-360-sample.bmp
     format: BMP
     type: BINARY
+  - id: online_rgb_bmp_8bit
+    url: https://samples-files.com/samples/images/bmp/480-360-sample.bmp
+    format: BMP
+    type: RGB
   - id: online_jpeg_image
     url: http://www.faqs.org/images/library.jpg
     format: JPEG

tests/components/openthread/test.esp32-c6-idf.yaml

@@ -1,3 +1,9 @@
+esp32:
+  board: esp32-c6-devkitc-1
+  framework:
+    type: esp-idf
+    log_level: DEBUG
+
 network:
   enable_ipv6: true
 
@@ -13,3 +19,4 @@ openthread:
   force_dataset: true
   use_address: open-thread-test.local
   poll_period: 20sec
+  output_power: 1dBm

tests/components/ota/test.nrf52-mcumgr.yaml

@@ -0,0 +1,27 @@
+zephyr_ble_server:
+
+ota:
+  - platform: zephyr_mcumgr
+    transport:
+      ble: true
+      hardware_uart: CDC
+    on_begin:
+      then:
+        - logger.log: "OTA start"
+    on_progress:
+      then:
+        - logger.log:
+            format: "OTA progress %0.1f%%"
+            args: ["x"]
+    on_end:
+      then:
+        - logger.log: "OTA end"
+    on_error:
+      then:
+        - logger.log:
+            format: "OTA update error %d"
+            args: ["x"]
+    on_state_change:
+      then:
+        lambda: >-
+          ESP_LOGD("ota", "State %d", state);

tests/components/packet_transport/binary_sensor/binary_sensor_test.cpp

@@ -0,0 +1,77 @@
+#include "../common.h"
+
+namespace esphome::packet_transport::testing {
+
+TEST(PacketTransportBinarySensorTest, AddBinarySensor) {
+  TestablePacketTransport transport;
+  binary_sensor::BinarySensor bs;
+  transport.add_binary_sensor("motion", &bs);
+  ASSERT_EQ(transport.binary_sensors_.size(), 1u);
+  EXPECT_STREQ(transport.binary_sensors_[0].id, "motion");
+  EXPECT_EQ(transport.binary_sensors_[0].sensor, &bs);
+}
+
+TEST(PacketTransportBinarySensorTest, AddRemoteBinarySensor) {
+  TestablePacketTransport transport;
+  binary_sensor::BinarySensor bs;
+  transport.add_remote_binary_sensor("host1", "remote_motion", &bs);
+  EXPECT_TRUE(transport.providers_.contains("host1"));
+  EXPECT_EQ(transport.remote_binary_sensors_["host1"]["remote_motion"], &bs);
+}
+
+TEST(PacketTransportBinarySensorTest, UnencryptedBinarySensorRoundTrip) {
+  TestablePacketTransport encoder;
+  encoder.init_for_test("sender");
+  binary_sensor::BinarySensor local_bs;
+  local_bs.state = true;
+  encoder.add_binary_sensor("motion", &local_bs);
+
+  encoder.send_data_(true);
+  ASSERT_EQ(encoder.sent_packets.size(), 1u);
+
+  TestablePacketTransport decoder;
+  decoder.init_for_test("receiver");
+  binary_sensor::BinarySensor remote_bs;
+  decoder.add_remote_binary_sensor("sender", "motion", &remote_bs);
+
+  auto &packet = encoder.sent_packets[0];
+  decoder.process_({packet.data(), packet.size()});
+  EXPECT_TRUE(remote_bs.state);
+}
+
+TEST(PacketTransportBinarySensorTest, MultipleSensorsRoundTrip) {
+  TestablePacketTransport encoder;
+  encoder.init_for_test("sender");
+
+  sensor::Sensor s1, s2;
+  s1.state = 10.0f;
+  s2.state = 20.0f;
+  encoder.add_sensor("s1", &s1);
+  encoder.add_sensor("s2", &s2);
+
+  binary_sensor::BinarySensor bs1;
+  bs1.state = true;
+  encoder.add_binary_sensor("bs1", &bs1);
+
+  encoder.send_data_(true);
+  ASSERT_EQ(encoder.sent_packets.size(), 1u);
+
+  TestablePacketTransport decoder;
+  decoder.init_for_test("receiver");
+  sensor::Sensor rs1, rs2;
+  binary_sensor::BinarySensor rbs1;
+  rs1.state = -999.0f;
+  rs2.state = -999.0f;
+  decoder.add_remote_sensor("sender", "s1", &rs1);
+  decoder.add_remote_sensor("sender", "s2", &rs2);
+  decoder.add_remote_binary_sensor("sender", "bs1", &rbs1);
+
+  auto &packet = encoder.sent_packets[0];
+  decoder.process_({packet.data(), packet.size()});
+
+  EXPECT_FLOAT_EQ(rs1.state, 10.0f);
+  EXPECT_FLOAT_EQ(rs2.state, 20.0f);
+  EXPECT_TRUE(rbs1.state);
+}
+
+}  // namespace esphome::packet_transport::testing

tests/components/packet_transport/common.h

@@ -0,0 +1,98 @@
+#pragma once
+#include <cstdint>
+#include <cstring>
+#include <cstdio>
+#include <vector>
+#include <gtest/gtest.h>
+#include "esphome/components/packet_transport/packet_transport.h"
+
+namespace esphome::packet_transport::testing {
+
+// Protocol constants mirrored from packet_transport.cpp for test packet construction.
+static constexpr uint16_t MAGIC_NUMBER = 0x4553;
+static constexpr uint16_t MAGIC_PING = 0x5048;
+
+// Concrete testable implementation of PacketTransport.
+// Captures sent packets and exposes protected members for verification.
+//
+// Sensor round-trip tests require USE_SENSOR / USE_BINARY_SENSOR to be defined,
+// which happens when 'sensor' and 'binary_sensor' components are in the build.
+// Run with --all or include those components to enable the full test suite.
+class TestablePacketTransport : public PacketTransport {
+ public:
+  using PacketTransport::add_key_;
+  using PacketTransport::data_;
+  using PacketTransport::encryption_key_;
+  using PacketTransport::flush_;
+  using PacketTransport::header_;
+  using PacketTransport::increment_code_;
+  using PacketTransport::init_data_;
+  using PacketTransport::is_encrypted_;
+  using PacketTransport::is_provider_;
+  using PacketTransport::name_;
+  using PacketTransport::ping_key_;
+  using PacketTransport::ping_keys_;
+  using PacketTransport::ping_pong_enable_;
+  using PacketTransport::ping_pong_recyle_time_;
+  using PacketTransport::process_;
+  using PacketTransport::providers_;
+  using PacketTransport::rolling_code_;
+  using PacketTransport::rolling_code_enable_;
+  using PacketTransport::send_data_;
+  using PacketTransport::updated_;
+#ifdef USE_SENSOR
+  using PacketTransport::add_data_;
+  using PacketTransport::remote_sensors_;
+  using PacketTransport::sensors_;
+#endif
+#ifdef USE_BINARY_SENSOR
+  using PacketTransport::add_binary_data_;
+  using PacketTransport::binary_sensors_;
+  using PacketTransport::remote_binary_sensors_;
+#endif
+
+  // NOTE: std::vector is used here for test convenience. For production code,
+  // consider using StaticVector or FixedVector from esphome/core/helpers.h instead.
+  mutable std::vector<std::vector<uint8_t>> sent_packets;
+  size_t max_packet_size{512};
+  bool send_enabled{true};
+
+  void send_packet(const std::vector<uint8_t> &buf) const override { this->sent_packets.push_back(buf); }
+  size_t get_max_packet_size() override { return this->max_packet_size; }
+  bool should_send() override { return this->send_enabled; }
+
+  /// Build the packet header for testing without requiring App or global_preferences.
+  void init_for_test(const char *name) {
+    this->name_ = name;
+    this->header_.clear();
+    // MAGIC_NUMBER as uint16_t little-endian
+    this->header_.push_back(MAGIC_NUMBER & 0xFF);
+    this->header_.push_back((MAGIC_NUMBER >> 8) & 0xFF);
+    // Length-prefixed hostname
+    auto len = strlen(name);
+    this->header_.push_back(static_cast<uint8_t>(len));
+    for (size_t i = 0; i < len; i++)
+      this->header_.push_back(name[i]);
+    // Pad to 4-byte boundary
+    while (this->header_.size() & 0x3)
+      this->header_.push_back(0);
+  }
+};
+
+/// Build a MAGIC_PING packet for testing add_key_ / ping-pong flows.
+inline std::vector<uint8_t> build_ping_packet(const char *hostname, uint32_t key) {
+  std::vector<uint8_t> packet;
+  packet.push_back(MAGIC_PING & 0xFF);
+  packet.push_back((MAGIC_PING >> 8) & 0xFF);
+  auto len = strlen(hostname);
+  packet.push_back(static_cast<uint8_t>(len));
+  for (size_t i = 0; i < len; i++)
+    packet.push_back(hostname[i]);
+  packet.push_back(key & 0xFF);
+  packet.push_back((key >> 8) & 0xFF);
+  packet.push_back((key >> 16) & 0xFF);
+  packet.push_back((key >> 24) & 0xFF);
+  return packet;
+}
+
+}  // namespace esphome::packet_transport::testing

tests/components/packet_transport/packet_transport_test.cpp

@@ -0,0 +1,186 @@
+#include "common.h"
+
+namespace esphome::packet_transport::testing {
+
+// --- Configuration setter tests ---
+
+TEST(PacketTransportTest, SetIsProvider) {
+  TestablePacketTransport transport;
+  transport.set_is_provider(true);
+  EXPECT_TRUE(transport.is_provider_);
+}
+
+TEST(PacketTransportTest, SetEncryptionKey) {
+  TestablePacketTransport transport;
+  std::vector<uint8_t> key(32, 0xAB);
+  transport.set_encryption_key(key);
+  EXPECT_EQ(transport.encryption_key_, key);
+  EXPECT_TRUE(transport.is_encrypted_());
+}
+
+TEST(PacketTransportTest, NoEncryptionByDefault) {
+  TestablePacketTransport transport;
+  EXPECT_FALSE(transport.is_encrypted_());
+}
+
+TEST(PacketTransportTest, SetRollingCodeEnable) {
+  TestablePacketTransport transport;
+  transport.set_rolling_code_enable(true);
+  EXPECT_TRUE(transport.rolling_code_enable_);
+}
+
+TEST(PacketTransportTest, SetPingPongEnable) {
+  TestablePacketTransport transport;
+  transport.set_ping_pong_enable(true);
+  EXPECT_TRUE(transport.ping_pong_enable_);
+}
+
+TEST(PacketTransportTest, SetPingPongRecycleTime) {
+  TestablePacketTransport transport;
+  transport.set_ping_pong_recycle_time(600);
+  EXPECT_EQ(transport.ping_pong_recyle_time_, 600u);
+}
+
+// --- Provider management ---
+
+TEST(PacketTransportTest, AddProvider) {
+  TestablePacketTransport transport;
+  transport.add_provider("host1");
+  EXPECT_TRUE(transport.providers_.contains("host1"));
+  EXPECT_EQ(transport.providers_.size(), 1u);
+}
+
+TEST(PacketTransportTest, AddProviderDuplicate) {
+  TestablePacketTransport transport;
+  transport.add_provider("host1");
+  transport.add_provider("host1");
+  EXPECT_EQ(transport.providers_.size(), 1u);
+}
+
+TEST(PacketTransportTest, SetProviderEncryption) {
+  TestablePacketTransport transport;
+  transport.add_provider("host1");
+  std::vector<uint8_t> key(32, 0xCD);
+  transport.set_provider_encryption("host1", key);
+  EXPECT_EQ(transport.providers_["host1"].encryption_key, key);
+}
+
+// --- Ping key tests ---
+
+TEST(PacketTransportTest, PingKeyStoredWhenEncrypted) {
+  TestablePacketTransport transport;
+  transport.init_for_test("receiver");
+  transport.set_encryption_key(std::vector<uint8_t>(32, 0xAA));
+
+  auto ping = build_ping_packet("requester", 0xDEADBEEF);
+  transport.process_({ping.data(), ping.size()});
+
+  ASSERT_EQ(transport.ping_keys_.size(), 1u);
+  EXPECT_EQ(transport.ping_keys_["requester"], 0xDEADBEEFu);
+}
+
+TEST(PacketTransportTest, PingKeyIgnoredWhenNotEncrypted) {
+  TestablePacketTransport transport;
+  transport.init_for_test("receiver");
+  // No encryption key — add_key_ should be a no-op
+
+  auto ping = build_ping_packet("requester", 0xDEADBEEF);
+  transport.process_({ping.data(), ping.size()});
+
+  EXPECT_TRUE(transport.ping_keys_.empty());
+}
+
+TEST(PacketTransportTest, PingKeyUpdatedOnRepeat) {
+  TestablePacketTransport transport;
+  transport.init_for_test("receiver");
+  transport.set_encryption_key(std::vector<uint8_t>(32, 0xAA));
+
+  auto ping1 = build_ping_packet("host1", 0x1111);
+  transport.process_({ping1.data(), ping1.size()});
+  EXPECT_EQ(transport.ping_keys_["host1"], 0x1111u);
+
+  // Same host, new key value — should update in place
+  auto ping2 = build_ping_packet("host1", 0x2222);
+  transport.process_({ping2.data(), ping2.size()});
+  EXPECT_EQ(transport.ping_keys_.size(), 1u);
+  EXPECT_EQ(transport.ping_keys_["host1"], 0x2222u);
+}
+
+TEST(PacketTransportTest, PingKeyMaxLimit) {
+  TestablePacketTransport transport;
+  transport.init_for_test("receiver");
+  transport.set_encryption_key(std::vector<uint8_t>(32, 0xAA));
+
+  // Fill to MAX_PING_KEYS (4)
+  for (int i = 0; i < 4; i++) {
+    char name[16];
+    snprintf(name, sizeof(name), "host%d", i);
+    auto ping = build_ping_packet(name, 0x1000 + i);
+    transport.process_({ping.data(), ping.size()});
+  }
+  EXPECT_EQ(transport.ping_keys_.size(), 4u);
+
+  // 5th key should be discarded
+  auto ping = build_ping_packet("host4", 0x9999);
+  transport.process_({ping.data(), ping.size()});
+  EXPECT_EQ(transport.ping_keys_.size(), 4u);
+  EXPECT_FALSE(transport.ping_keys_.contains("host4"));
+}
+
+// --- Process error handling ---
+
+TEST(PacketTransportTest, ProcessShortBuffer) {
+  TestablePacketTransport transport;
+  transport.init_for_test("receiver");
+  uint8_t buf[] = {0x53};
+  // Too short for a magic number - should return safely
+  transport.process_({buf, 1});
+}
+
+TEST(PacketTransportTest, ProcessBadMagic) {
+  TestablePacketTransport transport;
+  transport.init_for_test("receiver");
+  uint8_t buf[] = {0xFF, 0xFF, 0x00, 0x00};
+  // Wrong magic - should return safely
+  transport.process_({buf, sizeof(buf)});
+}
+
+TEST(PacketTransportTest, ProcessOwnHostname) {
+  TestablePacketTransport transport;
+  transport.init_for_test("myself");
+  // Build a packet from "myself" using a separate encoder
+  TestablePacketTransport fake_sender;
+  fake_sender.init_for_test("myself");
+  fake_sender.send_data_(true);
+  ASSERT_EQ(fake_sender.sent_packets.size(), 1u);
+
+  auto &packet = fake_sender.sent_packets[0];
+  // Should be silently ignored because hostname matches our own
+  transport.process_({packet.data(), packet.size()});
+}
+
+TEST(PacketTransportTest, ProcessUnknownHostname) {
+  TestablePacketTransport transport;
+  transport.init_for_test("receiver");
+  // No providers registered - "unknown" will not be found
+  TestablePacketTransport sender;
+  sender.init_for_test("unknown");
+  sender.send_data_(true);
+  ASSERT_EQ(sender.sent_packets.size(), 1u);
+
+  auto &packet = sender.sent_packets[0];
+  // Should return safely without crash
+  transport.process_({packet.data(), packet.size()});
+}
+
+// --- Send disabled ---
+
+TEST(PacketTransportTest, NoSendWhenDisabled) {
+  TestablePacketTransport transport;
+  transport.init_for_test("sender");
+  transport.send_enabled = false;
+  transport.send_data_(true);
+  EXPECT_TRUE(transport.sent_packets.empty());
+}
+
+}  // namespace esphome::packet_transport::testing

tests/components/packet_transport/sensor/sensor_test.cpp

@@ -0,0 +1,170 @@
+#include "../common.h"
+
+namespace esphome::packet_transport::testing {
+
+TEST(PacketTransportSensorTest, AddSensor) {
+  TestablePacketTransport transport;
+  sensor::Sensor s;
+  transport.add_sensor("temp", &s);
+  ASSERT_EQ(transport.sensors_.size(), 1u);
+  EXPECT_STREQ(transport.sensors_[0].id, "temp");
+  EXPECT_EQ(transport.sensors_[0].sensor, &s);
+  EXPECT_TRUE(transport.sensors_[0].updated);
+}
+
+TEST(PacketTransportSensorTest, AddRemoteSensor) {
+  TestablePacketTransport transport;
+  sensor::Sensor s;
+  transport.add_remote_sensor("host1", "remote_temp", &s);
+  EXPECT_TRUE(transport.providers_.contains("host1"));
+  EXPECT_EQ(transport.remote_sensors_["host1"]["remote_temp"], &s);
+}
+
+TEST(PacketTransportSensorTest, UnencryptedSensorRoundTrip) {
+  // Encoder
+  TestablePacketTransport encoder;
+  encoder.init_for_test("sender");
+  sensor::Sensor local_sensor;
+  local_sensor.state = 42.5f;
+  encoder.add_sensor("temp", &local_sensor);
+
+  encoder.send_data_(true);
+  ASSERT_EQ(encoder.sent_packets.size(), 1u);
+
+  // Decoder
+  TestablePacketTransport decoder;
+  decoder.init_for_test("receiver");
+  sensor::Sensor remote_sensor;
+  remote_sensor.state = -999.0f;  // sentinel
+  decoder.add_remote_sensor("sender", "temp", &remote_sensor);
+
+  auto &packet = encoder.sent_packets[0];
+  decoder.process_({packet.data(), packet.size()});
+  EXPECT_FLOAT_EQ(remote_sensor.state, 42.5f);
+}
+
+TEST(PacketTransportSensorTest, EncryptedSensorRoundTrip) {
+  std::vector<uint8_t> key(32);
+  for (int i = 0; i < 32; i++)
+    key[i] = i;
+
+  TestablePacketTransport encoder;
+  encoder.init_for_test("sender");
+  encoder.set_encryption_key(key);
+  sensor::Sensor local_sensor;
+  local_sensor.state = 99.9f;
+  encoder.add_sensor("temp", &local_sensor);
+
+  encoder.send_data_(true);
+  ASSERT_EQ(encoder.sent_packets.size(), 1u);
+
+  TestablePacketTransport decoder;
+  decoder.init_for_test("receiver");
+  sensor::Sensor remote_sensor;
+  remote_sensor.state = -999.0f;
+  decoder.add_remote_sensor("sender", "temp", &remote_sensor);
+  decoder.set_provider_encryption("sender", key);
+
+  auto &packet = encoder.sent_packets[0];
+  decoder.process_({packet.data(), packet.size()});
+  EXPECT_FLOAT_EQ(remote_sensor.state, 99.9f);
+}
+
+TEST(PacketTransportSensorTest, SendDataOnlyUpdated) {
+  TestablePacketTransport encoder;
+  encoder.init_for_test("sender");
+
+  sensor::Sensor s1, s2;
+  s1.state = 1.0f;
+  s2.state = 2.0f;
+  encoder.add_sensor("s1", &s1);
+  encoder.add_sensor("s2", &s2);
+
+  // Mark s1 as not updated, only s2 as updated
+  encoder.sensors_[0].updated = false;
+  encoder.sensors_[1].updated = true;
+
+  encoder.send_data_(false);
+  ASSERT_EQ(encoder.sent_packets.size(), 1u);
+
+  TestablePacketTransport decoder;
+  decoder.init_for_test("receiver");
+  sensor::Sensor rs1, rs2;
+  rs1.state = -999.0f;
+  rs2.state = -999.0f;
+  decoder.add_remote_sensor("sender", "s1", &rs1);
+  decoder.add_remote_sensor("sender", "s2", &rs2);
+
+  auto &packet = encoder.sent_packets[0];
+  decoder.process_({packet.data(), packet.size()});
+
+  EXPECT_FLOAT_EQ(rs1.state, -999.0f);  // not updated, not sent
+  EXPECT_FLOAT_EQ(rs2.state, 2.0f);     // updated, sent
+}
+
+TEST(PacketTransportSensorTest, PingKeyIncludedInTransmittedPacket) {
+  std::vector<uint8_t> key(32, 0xBB);
+
+  // Responder: encrypted, owns a sensor
+  TestablePacketTransport responder;
+  responder.init_for_test("responder");
+  responder.set_encryption_key(key);
+  sensor::Sensor local_sensor;
+  local_sensor.state = 77.7f;
+  responder.add_sensor("temp", &local_sensor);
+
+  // Requester sends a MAGIC_PING that the responder processes
+  auto ping = build_ping_packet("requester", 0xDEADBEEF);
+  responder.process_({ping.data(), ping.size()});
+  ASSERT_EQ(responder.ping_keys_.size(), 1u);
+
+  // Responder sends sensor data — ping key should be embedded
+  responder.send_data_(true);
+  ASSERT_EQ(responder.sent_packets.size(), 1u);
+
+  // Requester: encrypted provider, ping-pong enabled, expects key 0xDEADBEEF
+  TestablePacketTransport requester;
+  requester.init_for_test("requester");
+  requester.set_ping_pong_enable(true);
+  requester.ping_key_ = 0xDEADBEEF;
+  sensor::Sensor remote_sensor;
+  remote_sensor.state = -999.0f;
+  requester.add_remote_sensor("responder", "temp", &remote_sensor);
+  requester.set_provider_encryption("responder", key);
+
+  // The requester decrypts the packet and finds its ping key echoed back,
+  // which gates the sensor data — if the key is missing, data is blocked.
+  auto &packet = responder.sent_packets[0];
+  requester.process_({packet.data(), packet.size()});
+  EXPECT_FLOAT_EQ(remote_sensor.state, 77.7f);
+}
+
+TEST(PacketTransportSensorTest, MissingPingKeyBlocksSensorData) {
+  std::vector<uint8_t> key(32, 0xBB);
+
+  // Responder sends data WITHOUT receiving any MAGIC_PING first — no ping keys
+  TestablePacketTransport responder;
+  responder.init_for_test("responder");
+  responder.set_encryption_key(key);
+  sensor::Sensor local_sensor;
+  local_sensor.state = 77.7f;
+  responder.add_sensor("temp", &local_sensor);
+  responder.send_data_(true);
+  ASSERT_EQ(responder.sent_packets.size(), 1u);
+
+  // Requester with ping-pong enabled expects a key that isn't in the packet
+  TestablePacketTransport requester;
+  requester.init_for_test("requester");
+  requester.set_ping_pong_enable(true);
+  requester.ping_key_ = 0xDEADBEEF;
+  sensor::Sensor remote_sensor;
+  remote_sensor.state = -999.0f;
+  requester.add_remote_sensor("responder", "temp", &remote_sensor);
+  requester.set_provider_encryption("responder", key);
+
+  auto &packet = responder.sent_packets[0];
+  requester.process_({packet.data(), packet.size()});
+  EXPECT_FLOAT_EQ(remote_sensor.state, -999.0f);  // blocked — ping key not found
+}
+
+}  // namespace esphome::packet_transport::testing

tests/components/rp2040/test.rp2040-ard.yaml

@@ -1,3 +1,6 @@
+rp2040:
+  enable_full_printf: false
+
 logger:
   level: VERBOSE
 

tests/components/rp2040_ble/common.yaml

@@ -0,0 +1 @@
+rp2040_ble:

tests/components/rp2040_ble/test-disable-on-boot.rp2040-ard.yaml

@@ -0,0 +1,2 @@
+rp2040_ble:
+  enable_on_boot: false

tests/components/rp2040_ble/test.rp2040-ard.yaml

@@ -0,0 +1 @@
+<<: !include common.yaml

tests/components/serial_proxy/common.yaml

@@ -0,0 +1,10 @@
+wifi:
+  ssid: MySSID
+  password: password1
+
+api:
+
+serial_proxy:
+  - id: serial_proxy_1
+    name: Test Serial Port
+    port_type: RS232

tests/components/serial_proxy/test.esp32-idf.yaml

@@ -0,0 +1,8 @@
+substitutions:
+  tx_pin: GPIO4
+  rx_pin: GPIO5
+
+packages:
+  uart: !include ../../test_build_components/common/uart/esp32-idf.yaml
+
+<<: !include common.yaml

tests/components/serial_proxy/test.esp8266-ard.yaml

@@ -0,0 +1,8 @@
+substitutions:
+  tx_pin: GPIO0
+  rx_pin: GPIO2
+
+packages:
+  uart: !include ../../test_build_components/common/uart/esp8266-ard.yaml
+
+<<: !include common.yaml

tests/components/serial_proxy/test.rp2040-ard.yaml

@@ -0,0 +1,8 @@
+substitutions:
+  tx_pin: GPIO4
+  rx_pin: GPIO5
+
+packages:
+  uart: !include ../../test_build_components/common/uart/rp2040-ard.yaml
+
+<<: !include common.yaml

tests/components/speaker/common-media_player_off_on.yaml

@@ -0,0 +1,18 @@
+<<: !include common.yaml
+
+media_player:
+  - platform: speaker
+    id: speaker_media_player_id
+    announcement_pipeline:
+      speaker: speaker_id
+    buffer_size: 1000000
+    volume_increment: 0.02
+    volume_max: 0.95
+    volume_min: 0.0
+    task_stack_in_psram: true
+    on_turn_on:
+      then:
+        - logger.log: "Turn On Media Player"
+    on_turn_off:
+      then:
+        - logger.log: "Turn Off Media Player"

tests/components/speaker/media_player_off_on.esp32-idf.yaml

@@ -0,0 +1,9 @@
+substitutions:
+  scl_pin: GPIO16
+  sda_pin: GPIO17
+  i2s_bclk_pin: GPIO27
+  i2s_lrclk_pin: GPIO26
+  i2s_mclk_pin: GPIO25
+  i2s_dout_pin: GPIO23
+
+<<: !include common-media_player_off_on.yaml

tests/components/speaker_source/common.yaml

@@ -0,0 +1,43 @@
+i2s_audio:
+  i2s_lrclk_pin: ${i2s_bclk_pin}
+  i2s_bclk_pin: ${i2s_lrclk_pin}
+  i2s_mclk_pin: ${i2s_mclk_pin}
+
+speaker:
+  - platform: i2s_audio
+    id: speaker_id
+    dac_type: external
+    i2s_dout_pin: ${i2s_dout_pin}
+    sample_rate: 48000
+    num_channels: 2
+
+audio_file:
+  - id: test_audio
+    file:
+      type: local
+      path: $component_dir/test.wav
+
+media_source:
+  - platform: audio_file
+    id: audio_file_source
+
+media_player:
+  - platform: speaker_source
+    id: media_player_id
+    name: Media Player
+    volume_increment: 0.02
+    volume_initial: 0.75
+    volume_max: 0.95
+    volume_min: 0.0
+    media_pipeline:
+      speaker: speaker_id
+      format: FLAC
+      num_channels: 1
+      sources:
+        - audio_file_source
+    on_mute:
+      - media_player.pause:
+          id: media_player_id
+    on_unmute:
+      - media_player.play:
+          id: media_player_id

tests/components/speaker_source/test.esp32-idf.yaml

@@ -0,0 +1,9 @@
+substitutions:
+  scl_pin: GPIO16
+  sda_pin: GPIO17
+  i2s_bclk_pin: GPIO27
+  i2s_lrclk_pin: GPIO26
+  i2s_mclk_pin: GPIO25
+  i2s_dout_pin: GPIO23
+
+<<: !include common.yaml

tests/components/template/common-base.yaml

@@ -28,9 +28,14 @@ esphome:
     # Test C++ API: set_template() with stateless lambda (no captures)
     # NOTE: set_template() is not intended to be a public API, but we test it to ensure it doesn't break.
     - lambda: |-
-        id(template_sens).set_template([]() -> esphome::optional<float> {
+        id(template_sens).set_template([]() -> std::optional<float> {
           return 123.0f;
         });
+    # Test that esphome::optional alias still works for backward compatibility
+    - lambda: |-
+        id(template_sens).set_template([]() -> esphome::optional<float> {
+          return 42.0f;
+        });
 
     - datetime.date.set:
         id: test_date

tests/components/uart/common.h

@@ -30,7 +30,7 @@ class MockUARTComponent : public UARTComponent {
   MOCK_METHOD(bool, read_array, (uint8_t * data, size_t len), (override));
   MOCK_METHOD(bool, peek_byte, (uint8_t * data), (override));
   MOCK_METHOD(size_t, available, (), (override));
-  MOCK_METHOD(void, flush, (), (override));
+  MOCK_METHOD(FlushResult, flush, (), (override));
   MOCK_METHOD(void, check_logger_conflict, (), (override));
 };
 

tests/components/uart/test.esp32-c3-idf.yaml

@@ -1,11 +1,15 @@
 esphome:
   on_boot:
     then:
-      - uart.write: 'Hello World'
-      - uart.write: [0x00, 0x20, 0x42]
+      - uart.write:
+          id: uart_id
+          data: 'Hello World'
+      - uart.write:
+          id: uart_id
+          data: [0x00, 0x20, 0x42]
 
 uart:
-  - id: uart_uart
+  - id: uart_id
     tx_pin: 4
     rx_pin: 5
     flow_control_pin: 6
@@ -16,3 +20,9 @@ uart:
     rx_timeout: 1
     parity: EVEN
     stop_bits: 2
+  - id: uart_debug
+    tx_pin: 18
+    rx_pin: 19
+    baud_rate: 115200
+    debug:
+      debug_prefix: "[UART1] "

tests/components/uart/test.esp32-idf.yaml

@@ -1,13 +1,19 @@
 esphome:
   on_boot:
     then:
-      - uart.write: 'Hello World'
-      - uart.write: [0x00, 0x20, 0x42]
-      - uart.write: !lambda |-
-          return {0xAA, 0xBB, 0xCC};
+      - uart.write:
+          id: uart_id
+          data: 'Hello World'
+      - uart.write:
+          id: uart_id
+          data: [0x00, 0x20, 0x42]
+      - uart.write:
+          id: uart_id
+          data: !lambda |-
+            return {0xAA, 0xBB, 0xCC};
 
 uart:
-  - id: uart_uart
+  - id: uart_id
     tx_pin: 17
     rx_pin: 16
     flow_control_pin: 4
@@ -18,32 +24,54 @@ uart:
     rx_timeout: 1
     parity: EVEN
     stop_bits: 2
+  - id: uart_debug
+    tx_pin: 21
+    rx_pin: 22
+    baud_rate: 115200
+    debug:
+      debug_prefix: "[UART1] "
+  - id: uart_debug_custom
+    tx_pin: 25
+    rx_pin: 26
+    baud_rate: 9600
+    debug:
+      debug_prefix: "[UART2] "
+      after:
+        delimiter: "\n"
+      sequence:
+        - lambda: UARTDebug::log_string(direction, bytes, debug_prefix);
+  - id: uart_debug_no_prefix
+    tx_pin: 32
+    rx_pin: 33
+    baud_rate: 9600
+    debug:
 
 packet_transport:
   - platform: uart
+    uart_id: uart_id
 
 switch:
   # Test uart switch with single state (array)
   - platform: uart
     name: "UART Switch Single Array"
-    uart_id: uart_uart
+    uart_id: uart_id
     data: [0x01, 0x02, 0x03]
   # Test uart switch with single state (string)
   - platform: uart
     name: "UART Switch Single String"
-    uart_id: uart_uart
+    uart_id: uart_id
     data: "ON"
   # Test uart switch with turn_on/turn_off (arrays)
   - platform: uart
     name: "UART Switch Dual Array"
-    uart_id: uart_uart
+    uart_id: uart_id
     data:
       turn_on: [0xA0, 0xA1, 0xA2]
       turn_off: [0xB0, 0xB1, 0xB2]
   # Test uart switch with turn_on/turn_off (strings)
   - platform: uart
     name: "UART Switch Dual String"
-    uart_id: uart_uart
+    uart_id: uart_id
     data:
       turn_on: "TURN_ON"
       turn_off: "TURN_OFF"
@@ -61,24 +89,26 @@ button:
   # Test uart button with array data
   - platform: uart
     name: "UART Button Array"
-    uart_id: uart_uart
+    uart_id: uart_id
     data: [0xFF, 0xEE, 0xDD]
   # Test uart button with string data
   - platform: uart
     name: "UART Button String"
-    uart_id: uart_uart
+    uart_id: uart_id
     data: "BUTTON_PRESS"
   # Test uart button with lambda (function pointer)
   - platform: template
     name: "UART Lambda Test"
     on_press:
-      - uart.write: !lambda |-
-          std::string cmd = "VALUE=" + str_sprintf("%.0f", id(test_number).state) + "\r\n";
-          return std::vector<uint8_t>(cmd.begin(), cmd.end());
+      - uart.write:
+          id: uart_id
+          data: !lambda |-
+            std::string cmd = "VALUE=" + str_sprintf("%.0f", id(test_number).state) + "\r\n";
+            return std::vector<uint8_t>(cmd.begin(), cmd.end());
 
 event:
   - platform: uart
-    uart_id: uart_uart
+    uart_id: uart_id
     name: "UART Event"
     event_types:
       - "string_event_A": "*A#"

tests/components/uart/test.esp8266-ard.yaml

@@ -1,11 +1,15 @@
 esphome:
   on_boot:
     then:
-      - uart.write: 'Hello World'
-      - uart.write: [0x00, 0x20, 0x42]
+      - uart.write:
+          id: uart_id
+          data: 'Hello World'
+      - uart.write:
+          id: uart_id
+          data: [0x00, 0x20, 0x42]
 
 uart:
-  - id: uart_uart
+  - id: uart_id
     tx_pin: 4
     rx_pin: 5
     baud_rate: 9600
@@ -13,15 +17,21 @@ uart:
     rx_buffer_size: 512
     parity: EVEN
     stop_bits: 2
+  - id: uart_debug
+    tx_pin: 14
+    rx_pin: 12
+    baud_rate: 115200
+    debug:
+      debug_prefix: "[UART1] "
 
 switch:
   - platform: uart
     name: "UART Switch Array"
-    uart_id: uart_uart
+    uart_id: uart_id
     data: [0x01, 0x02, 0x03]
   - platform: uart
     name: "UART Switch Dual"
-    uart_id: uart_uart
+    uart_id: uart_id
     data:
       turn_on: [0xA0, 0xA1]
       turn_off: [0xB0, 0xB1]
@@ -29,12 +39,12 @@ switch:
 button:
   - platform: uart
     name: "UART Button"
-    uart_id: uart_uart
+    uart_id: uart_id
     data: [0xFF, 0xEE]
 
 event:
   - platform: uart
-    uart_id: uart_uart
+    uart_id: uart_id
     name: "UART Event"
     event_types:
       - "string_event_A": "*A#"

tests/components/uart/test.host.yaml

@@ -5,7 +5,7 @@ esphome:
       - uart.write: [0x00, 0x20, 0x42]
 
 uart:
-  - id: uart_uart
+  - id: uart_id
     port: "/dev/ttyS0"
     baud_rate: 9600
     data_bits: 8

tests/components/uart/test.rp2040-ard.yaml

@@ -1,11 +1,15 @@
 esphome:
   on_boot:
     then:
-      - uart.write: 'Hello World'
-      - uart.write: [0x00, 0x20, 0x42]
+      - uart.write:
+          id: uart_id
+          data: 'Hello World'
+      - uart.write:
+          id: uart_id
+          data: [0x00, 0x20, 0x42]
 
 uart:
-  - id: uart_uart
+  - id: uart_id
     tx_pin: 4
     rx_pin: 5
     baud_rate: 9600
@@ -13,3 +17,9 @@ uart:
     rx_buffer_size: 512
     parity: EVEN
     stop_bits: 2
+  - id: uart_debug
+    tx_pin: 8
+    rx_pin: 9
+    baud_rate: 115200
+    debug:
+      debug_prefix: "[UART1] "

tests/components/usb_uart/common.yaml

@@ -34,3 +34,11 @@ usb_uart:
       - id: channel_4_1
         debug: true
         dummy_receiver: true
+        debug_prefix: "[ESP_JTAG] "
+  - id: uart_5
+    type: cp210x
+    channels:
+      - id: channel_5_1
+        baud_rate: 9600
+        debug: true
+        debug_prefix: "[CP210X] "

tests/dummy_main.cpp

@@ -12,7 +12,9 @@
 using namespace esphome;
 
 void setup() {
-  App.pre_setup("livingroom", "LivingRoom", false);
+  static char name[] = "livingroom";
+  static char friendly_name[] = "LivingRoom";
+  App.pre_setup(name, sizeof(name) - 1, friendly_name, sizeof(friendly_name) - 1);
   auto *log = new logger::Logger(115200);  // NOLINT
   log->pre_setup();
   log->set_uart_selection(logger::UART_SELECTION_UART0);

tests/integration/conftest.py

@@ -73,11 +73,6 @@ def shared_platformio_cache() -> Generator[Path]:
     test_cache_dir = Path.home() / ".esphome-integration-tests"
     cache_dir = test_cache_dir / "platformio"
 
-    # Create the temp directory that PlatformIO uses to avoid race conditions
-    # This ensures it exists and won't be deleted by parallel processes
-    platformio_tmp_dir = cache_dir / ".cache" / "tmp"
-    platformio_tmp_dir.mkdir(parents=True, exist_ok=True)
-
     # Use a lock file in the home directory to ensure only one process initializes the cache
     # This is needed when running with pytest-xdist
     # The lock file must be in a directory that already exists to avoid race conditions
@@ -87,8 +82,9 @@ def shared_platformio_cache() -> Generator[Path]:
     with open(lock_file, "w") as lock_fd:
         fcntl.flock(lock_fd.fileno(), fcntl.LOCK_EX)
 
-        # Check if cache needs initialization while holding the lock
-        if not cache_dir.exists() or not any(cache_dir.iterdir()):
+        # Check if the native platform is installed (the actual indicator of a populated cache)
+        native_platform = cache_dir / "platforms" / "native"
+        if not native_platform.exists():
             # Create the test cache directory if it doesn't exist
             test_cache_dir.mkdir(exist_ok=True)
 
@@ -197,6 +193,7 @@ async def yaml_config(request: pytest.FixtureRequest, unused_tcp_port: int) -> s
             "  platformio_options:\n"
             "    build_flags:\n"
             '      - "-DDEBUG"  # Enable assert() statements\n'
+            '      - "-DESPHOME_DEBUG"  # Enable ESPHOME_DEBUG_ASSERT checks\n'
             '      - "-DESPHOME_DEBUG_API"  # Enable API protocol asserts\n'
             '      - "-g"       # Add debug symbols',
         )

tests/integration/fixtures/external_components/uart_mock/__init__.py

@@ -0,0 +1,174 @@
+from esphome import automation
+import esphome.codegen as cg
+from esphome.components import uart
+from esphome.components.const import CONF_DATA_BITS, CONF_PARITY, CONF_STOP_BITS
+from esphome.components.uart import (
+    CONF_RX_FULL_THRESHOLD,
+    CONF_RX_TIMEOUT,
+    debug_to_code,
+    maybe_empty_debug,
+    validate_raw_data,
+)
+import esphome.config_validation as cv
+from esphome.const import (
+    CONF_BAUD_RATE,
+    CONF_DATA,
+    CONF_DEBUG,
+    CONF_DELAY,
+    CONF_ID,
+    CONF_INTERVAL,
+    CONF_RX_BUFFER_SIZE,
+    CONF_TRIGGER_ID,
+)
+from esphome.core import ID
+
+CODEOWNERS = ["@esphome/tests"]
+MULTI_CONF = True
+
+uart_mock_ns = cg.esphome_ns.namespace("uart_mock")
+MockUartComponent = uart_mock_ns.class_(
+    "MockUartComponent", uart.UARTComponent, cg.Component
+)
+MockUartInjectRXAction = uart_mock_ns.class_(
+    "MockUartInjectRXAction", automation.Action
+)
+MockUartTXTrigger = uart_mock_ns.class_(
+    "MockUartTXTrigger",
+    automation.Trigger.template(cg.std_vector.template(cg.uint8)),
+)
+
+CONF_INJECTIONS = "injections"
+CONF_RESPONSES = "responses"
+CONF_INJECT_RX = "inject_rx"
+CONF_EXPECT_TX = "expect_tx"
+CONF_PERIODIC_RX = "periodic_rx"
+CONF_ON_TX = "on_tx"
+CONF_AUTO_START = "auto_start"
+
+UART_PARITY_OPTIONS = {
+    "NONE": uart.UARTParityOptions.UART_CONFIG_PARITY_NONE,
+    "EVEN": uart.UARTParityOptions.UART_CONFIG_PARITY_EVEN,
+    "ODD": uart.UARTParityOptions.UART_CONFIG_PARITY_ODD,
+}
+
+INJECTION_SCHEMA = cv.Schema(
+    {
+        cv.Required(CONF_INJECT_RX): [cv.hex_uint8_t],
+        cv.Optional(CONF_DELAY, default="0ms"): cv.positive_time_period_milliseconds,
+    }
+)
+
+CONFIG_INJECT_RX_SCHEMA = cv.maybe_simple_value(
+    {
+        cv.GenerateID(): cv.use_id(MockUartComponent),
+        cv.Required("data"): cv.templatable(validate_raw_data),
+        cv.Optional(CONF_DELAY): cv.positive_time_period_milliseconds,
+    },
+    key=CONF_DATA,
+)
+
+
+RESPONSE_SCHEMA = cv.Schema(
+    {
+        cv.Required(CONF_EXPECT_TX): [cv.hex_uint8_t],
+        cv.Required(CONF_INJECT_RX): [cv.hex_uint8_t],
+        cv.Optional(CONF_DELAY, default="0ms"): cv.positive_time_period_milliseconds,
+    }
+)
+
+PERIODIC_RX_SCHEMA = cv.Schema(
+    {
+        cv.Required(CONF_DATA): [cv.hex_uint8_t],
+        cv.Required(CONF_INTERVAL): cv.positive_time_period_milliseconds,
+    }
+)
+
+CONFIG_SCHEMA = cv.Schema(
+    {
+        cv.GenerateID(): cv.declare_id(MockUartComponent),
+        cv.Required(CONF_BAUD_RATE): cv.int_range(min=1),
+        cv.Optional(CONF_RX_BUFFER_SIZE, default=256): cv.validate_bytes,
+        cv.Optional(CONF_RX_FULL_THRESHOLD): cv.int_range(min=1, max=120),
+        cv.Optional(CONF_RX_TIMEOUT, default=2): cv.int_range(min=0, max=92),
+        cv.Optional(CONF_STOP_BITS, default=1): cv.one_of(1, 2, int=True),
+        cv.Optional(CONF_DATA_BITS, default=8): cv.int_range(min=5, max=8),
+        cv.Optional(CONF_PARITY, default="NONE"): cv.enum(
+            UART_PARITY_OPTIONS, upper=True
+        ),
+        cv.Optional(CONF_INJECTIONS, default=[]): cv.ensure_list(INJECTION_SCHEMA),
+        cv.Optional(CONF_RESPONSES, default=[]): cv.ensure_list(RESPONSE_SCHEMA),
+        cv.Optional(CONF_PERIODIC_RX, default=[]): cv.ensure_list(PERIODIC_RX_SCHEMA),
+        cv.Optional(CONF_AUTO_START, default=True): cv.boolean,
+        cv.Optional(CONF_ON_TX): automation.validate_automation(
+            {
+                cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(MockUartTXTrigger),
+            }
+        ),
+        cv.Optional(CONF_DEBUG): maybe_empty_debug,
+    }
+).extend(cv.COMPONENT_SCHEMA)
+
+
+@automation.register_action(
+    "uart_mock.inject_rx", MockUartInjectRXAction, CONFIG_INJECT_RX_SCHEMA
+)
+async def inject_rx_to_code(config, action_id, template_arg, args):
+    var = cg.new_Pvariable(action_id, template_arg)
+    await cg.register_parented(var, config[CONF_ID])
+    data = config[CONF_DATA]
+    if isinstance(data, bytes):
+        data = list(data)
+
+    if cg.is_template(data):
+        templ = await cg.templatable(data, args, cg.std_vector.template(cg.uint8))
+        cg.add(var.set_data_template(templ))
+    else:
+        # Generate static array in flash to avoid RAM copy
+        arr_id = ID(f"{action_id}_data", is_declaration=True, type=cg.uint8)
+        arr = cg.static_const_array(arr_id, cg.ArrayInitializer(*data))
+        cg.add(var.set_data_static(arr, len(data)))
+    if CONF_DELAY in config:
+        cg.add(var.set_delay(config[CONF_DELAY]))
+    return var
+
+
+async def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    await cg.register_component(var, config)
+
+    cg.add(var.set_baud_rate(config[CONF_BAUD_RATE]))
+    cg.add(var.set_rx_buffer_size(config[CONF_RX_BUFFER_SIZE]))
+    if CONF_RX_FULL_THRESHOLD in config:
+        cg.add(var.set_rx_full_threshold(config[CONF_RX_FULL_THRESHOLD]))
+    cg.add(var.set_rx_timeout(config[CONF_RX_TIMEOUT]))
+    cg.add(var.set_stop_bits(config[CONF_STOP_BITS]))
+    cg.add(var.set_data_bits(config[CONF_DATA_BITS]))
+    cg.add(var.set_parity(config[CONF_PARITY]))
+
+    if not config[CONF_AUTO_START]:
+        cg.add(var.set_auto_start(False))
+
+    for injection in config[CONF_INJECTIONS]:
+        rx_data = injection[CONF_INJECT_RX]
+        delay_ms = injection[CONF_DELAY]
+        cg.add(var.add_injection(rx_data, delay_ms))
+
+    for response in config[CONF_RESPONSES]:
+        tx_data = response[CONF_EXPECT_TX]
+        rx_data = response[CONF_INJECT_RX]
+        delay_ms = response[CONF_DELAY]
+        cg.add(var.add_response(tx_data, rx_data, delay_ms))
+
+    for periodic in config[CONF_PERIODIC_RX]:
+        data = periodic[CONF_DATA]
+        interval = periodic[CONF_INTERVAL]
+        cg.add(var.add_periodic_rx(data, interval))
+
+    for conf in config.get(CONF_ON_TX, []):
+        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
+        await automation.build_automation(
+            trigger, [(cg.std_vector.template(cg.uint8), "data")], conf
+        )
+
+    if CONF_DEBUG in config:
+        await debug_to_code(config[CONF_DEBUG], var)

tests/integration/fixtures/external_components/uart_mock/automation.h

@@ -0,0 +1,63 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/core/automation.h"
+#include "uart_mock.h"
+
+namespace esphome::uart_mock {
+
+// This pattern is similar to UARTWriteAction but calls inject_rx instead of write_array, and is parented to VirtualUART
+// instead of UARTComponent
+template<typename... Ts> class MockUartInjectRXAction : public Action<Ts...>, public Parented<MockUartComponent> {
+ public:
+  void set_data_template(std::vector<uint8_t> (*func)(Ts...)) {
+    // Stateless lambdas (generated by ESPHome) implicitly convert to function pointers
+    this->code_.func = func;
+    this->len_ = -1;  // Sentinel value indicates template mode
+  }
+
+  // Store pointer to static data in flash (no RAM copy)
+  void set_data_static(const uint8_t *data, size_t len) {
+    this->code_.data = data;
+    this->len_ = len;  // Length >= 0 indicates static mode
+  }
+
+  void set_delay(uint32_t delay_ms) { this->delay_ms_ = delay_ms; }
+
+  void play(const Ts &...x) override {
+    if (this->len_ >= 0) {
+      // Static mode: use pointer and length
+      if (this->delay_ms_ > 0) {
+        std::vector<uint8_t> data(this->code_.data, this->code_.data + this->len_);
+        this->parent_->inject_to_rx_buffer_delayed(data, this->delay_ms_);
+      } else {
+        this->parent_->inject_to_rx_buffer(this->code_.data, static_cast<size_t>(this->len_));
+      }
+    } else {
+      // Template mode: call function
+      auto val = this->code_.func(x...);
+      if (this->delay_ms_ > 0) {
+        this->parent_->inject_to_rx_buffer_delayed(val, this->delay_ms_);
+      } else {
+        this->parent_->inject_to_rx_buffer(val);
+      }
+    }
+  }
+
+ protected:
+  uint32_t delay_ms_{0};
+  ssize_t len_{-1};  // -1 = template mode, >=0 = static mode with length
+  union Code {
+    std::vector<uint8_t> (*func)(Ts...);  // Function pointer (stateless lambdas)
+    const uint8_t *data;                  // Pointer to static data in flash
+  } code_;
+};
+
+class MockUartTXTrigger : public Trigger<std::vector<uint8_t>> {
+ public:
+  explicit MockUartTXTrigger(MockUartComponent *parent) {
+    parent->set_tx_hook([this](std::vector<uint8_t> data) { this->trigger(data); });
+  }
+};
+
+}  // namespace esphome::uart_mock

tests/integration/fixtures/external_components/uart_mock/uart_mock.cpp

@@ -0,0 +1,232 @@
+// Host-only test component — do not copy to production code.
+// See uart_mock.h for details.
+
+#include "uart_mock.h"
+#include "esphome/core/application.h"
+#include "esphome/core/helpers.h"
+#include "esphome/core/log.h"
+
+namespace esphome::uart_mock {
+
+static const char *const TAG = "uart_mock";
+
+void MockUartComponent::setup() {
+  ESP_LOGI(TAG, "Mock UART initialized with %zu injections, %zu responses, %zu periodic", this->injections_.size(),
+           this->responses_.size(), this->periodic_rx_.size());
+}
+
+void MockUartComponent::loop() {
+  if (!this->loop_started_) {
+    this->loop_started_ = true;
+    if (this->auto_start_) {
+      this->start_scenario();
+    } else {
+      ESP_LOGD(TAG, "Scenario waiting for manual start");
+    }
+  }
+
+  if (!this->scenario_active_) {
+    return;
+  }
+
+  uint32_t now = App.get_loop_component_start_time();
+
+  // Process at most ONE timed injection per loop iteration.
+  // This ensures each injection is in a separate loop cycle, giving the consuming
+  // component (e.g., LD2410) a chance to process each batch independently.
+  if (this->injection_index_ < this->injections_.size()) {
+    auto &injection = this->injections_[this->injection_index_];
+    uint32_t total_delay = this->cumulative_delay_ms_ + injection.delay_ms;
+    if (now - this->scenario_start_ms_ >= total_delay) {
+      ESP_LOGD(TAG, "Injecting %zu RX bytes (injection %u)", injection.rx_data.size(), this->injection_index_);
+      this->inject_to_rx_buffer(injection.rx_data);
+      this->cumulative_delay_ms_ += injection.delay_ms;
+      this->injection_index_++;
+    }
+  }
+
+  // Process periodic RX
+  for (auto &periodic : this->periodic_rx_) {
+    if (now - periodic.last_inject_ms >= periodic.interval_ms) {
+      this->inject_to_rx_buffer(periodic.data);
+      periodic.last_inject_ms = now;
+    }
+  }
+
+  // Process staged RX - deliver bytes whose delay has elapsed
+  uint32_t now_ms = millis();
+  while (!this->staged_rx_.empty() && (static_cast<int32_t>(now_ms - this->staged_rx_.front().available_at_ms) >= 0)) {
+    auto &staged = this->staged_rx_.front();
+    ESP_LOGD(TAG, "Delivering %zu staged RX bytes", staged.data.size());
+    this->inject_to_rx_buffer(staged.data);
+    this->staged_rx_.pop_front();
+  }
+
+  // Process delayed responses
+  for (auto &response : this->responses_) {
+    if (response.delay_ms > 0 && response.last_match_ms > 0 && now - response.last_match_ms >= response.delay_ms) {
+      ESP_LOGD(TAG, "Injecting %zu RX bytes for delayed response", response.inject_rx.size());
+      this->inject_to_rx_buffer(response.inject_rx);
+      response.last_match_ms = 0;  // Reset to prevent repeated injection
+    }
+  }
+}
+
+void MockUartComponent::start_scenario() {
+  uint32_t now = App.get_loop_component_start_time();
+  this->scenario_active_ = true;
+  this->scenario_start_ms_ = now;
+  this->cumulative_delay_ms_ = 0;
+  this->injection_index_ = 0;
+  this->tx_buffer_.clear();
+  for (auto &periodic : this->periodic_rx_) {
+    periodic.last_inject_ms = now;
+  }
+  ESP_LOGD(TAG, "Scenario started at %u ms", now);
+}
+
+void MockUartComponent::dump_config() {
+  ESP_LOGCONFIG(TAG,
+                "Mock UART Component:\n"
+                "  Baud Rate: %u\n"
+                "  Injections: %zu\n"
+                "  Responses: %zu\n"
+                "  Periodic RX: %zu",
+                this->baud_rate_, this->injections_.size(), this->responses_.size(), this->periodic_rx_.size());
+}
+
+void MockUartComponent::write_array(const uint8_t *data, size_t len) {
+  this->tx_count_ += len;
+  this->tx_buffer_.insert(this->tx_buffer_.end(), data, data + len);
+
+  // Log all TX data so tests can verify what the component sends
+  if (len > 0 && len <= 64) {
+    char hex_buf[format_hex_pretty_size(64)];
+    ESP_LOGD(TAG, "TX %zu bytes: %s", len, format_hex_pretty_to(hex_buf, sizeof(hex_buf), data, len));
+  } else if (len > 64) {
+    ESP_LOGD(TAG, "TX %zu bytes (too large to log)", len);
+  }
+
+#ifdef USE_UART_DEBUGGER
+  for (size_t i = 0; i < len; i++) {
+    this->debug_callback_.call(uart::UART_DIRECTION_TX, data[i]);
+  }
+#endif
+
+  // Responses are always active - they are request-response pairs triggered by
+  // component TX, not timed injections. No race condition with test subscription.
+  this->try_match_response_();
+
+  // This directly calls a tx_hook (lambda) as an alternative to the simpler match_response mechanism.
+  if (this->tx_hook_) {
+    std::vector<uint8_t> buf(data, data + len);
+    this->tx_hook_(buf);
+  }
+}
+
+bool MockUartComponent::peek_byte(uint8_t *data) {
+  if (this->rx_buffer_.empty()) {
+    return false;
+  }
+  *data = this->rx_buffer_.front();
+  return true;
+}
+
+bool MockUartComponent::read_array(uint8_t *data, size_t len) {
+  if (this->rx_buffer_.size() < len) {
+    return false;
+  }
+  for (size_t i = 0; i < len; i++) {
+    data[i] = this->rx_buffer_.front();
+    this->rx_buffer_.pop_front();
+  }
+  this->rx_count_ += len;
+
+#ifdef USE_UART_DEBUGGER
+  for (size_t i = 0; i < len; i++) {
+    this->debug_callback_.call(uart::UART_DIRECTION_RX, data[i]);
+  }
+#endif
+
+  return true;
+}
+
+size_t MockUartComponent::available() { return this->rx_buffer_.size(); }
+
+uart::FlushResult MockUartComponent::flush() {
+  // Nothing to flush in mock
+  return uart::FlushResult::ASSUMED_SUCCESS;
+}
+
+void MockUartComponent::set_rx_full_threshold(size_t rx_full_threshold) {
+  this->rx_full_threshold_ = rx_full_threshold;
+}
+
+void MockUartComponent::set_rx_timeout(size_t rx_timeout) { this->rx_timeout_ = rx_timeout; }
+
+void MockUartComponent::add_injection(const std::vector<uint8_t> &rx_data, uint32_t delay_ms) {
+  this->injections_.push_back({rx_data, delay_ms});
+}
+
+void MockUartComponent::add_response(const std::vector<uint8_t> &expect_tx, const std::vector<uint8_t> &inject_rx,
+                                     uint32_t delay_ms) {
+  this->responses_.push_back({expect_tx, inject_rx, delay_ms, 0});
+}
+
+void MockUartComponent::add_periodic_rx(const std::vector<uint8_t> &data, uint32_t interval_ms) {
+  this->periodic_rx_.push_back({data, interval_ms, 0});
+}
+
+void MockUartComponent::try_match_response_() {
+  for (auto &response : this->responses_) {
+    if (this->tx_buffer_.size() < response.expect_tx.size()) {
+      continue;
+    }
+    // Check if tx_buffer_ ends with expect_tx
+    size_t offset = this->tx_buffer_.size() - response.expect_tx.size();
+    if (std::equal(response.expect_tx.begin(), response.expect_tx.end(), this->tx_buffer_.begin() + offset)) {
+      ESP_LOGD(TAG, "TX match found, injecting %zu RX bytes", response.inject_rx.size());
+      if (response.delay_ms > 0) {
+        ESP_LOGD(TAG, "Delaying response by %u ms", response.delay_ms);
+        // Schedule the response injection as a future injection
+        response.last_match_ms = App.get_loop_component_start_time();
+      } else {
+        this->inject_to_rx_buffer(response.inject_rx);
+      }
+      this->tx_buffer_.clear();
+      return;
+    }
+  }
+}
+
+void MockUartComponent::inject_to_rx_buffer(const uint8_t *data, size_t len) {
+  std::vector<uint8_t> vec(data, data + len);
+  this->inject_to_rx_buffer(vec);
+}
+
+void MockUartComponent::inject_to_rx_buffer(const std::vector<uint8_t> &data) {
+  // Log injected RX data so tests can see what's being fed to the component
+  if (!data.empty() && data.size() <= 64) {
+    char hex_buf[format_hex_pretty_size(64)];
+    ESP_LOGD(TAG, "RX inject %zu bytes: %s", data.size(),
+             format_hex_pretty_to(hex_buf, sizeof(hex_buf), data.data(), data.size()));
+  } else if (data.size() > 64) {
+    ESP_LOGD(TAG, "RX inject %zu bytes (too large to log inline)", data.size());
+  }
+  for (uint8_t byte : data) {
+    this->rx_buffer_.push_back(byte);
+  }
+}
+
+void MockUartComponent::inject_to_rx_buffer_delayed(const std::vector<uint8_t> &data, uint32_t delay_ms) {
+  if (!data.empty() && data.size() <= 64) {
+    char hex_buf[format_hex_pretty_size(64)];
+    ESP_LOGD(TAG, "Staging %zu RX bytes with %ums delay: %s", data.size(), delay_ms,
+             format_hex_pretty_to(hex_buf, sizeof(hex_buf), data.data(), data.size()));
+  } else if (data.size() > 64) {
+    ESP_LOGD(TAG, "Staging %zu RX bytes with %ums delay (too large to log inline)", data.size(), delay_ms);
+  }
+  this->staged_rx_.push_back({data, millis() + delay_ms});
+}
+
+}  // namespace esphome::uart_mock

tests/integration/fixtures/external_components/uart_mock/uart_mock.h

@@ -0,0 +1,103 @@
+#pragma once
+
+// ============================================================================
+// HOST-ONLY TEST COMPONENT — DO NOT COPY TO PRODUCTION CODE
+//
+// This component runs exclusively on the host platform for integration testing.
+// It intentionally uses std::vector, std::deque, and dynamic allocation which
+// would be inappropriate for production embedded components. Do not use this
+// code as a reference for writing ESPHome components targeting real hardware.
+// ============================================================================
+
+#include "esphome/core/component.h"
+#include "esphome/components/uart/uart_component.h"
+#include <deque>
+#include <vector>
+
+namespace esphome::uart_mock {
+
+class MockUartComponent : public uart::UARTComponent, public Component {
+ public:
+  void setup() override;
+  void loop() override;
+  void dump_config() override;
+  float get_setup_priority() const override { return setup_priority::BUS; }
+
+  // UARTComponent interface
+  void write_array(const uint8_t *data, size_t len) override;
+  bool peek_byte(uint8_t *data) override;
+  bool read_array(uint8_t *data, size_t len) override;
+  size_t available() override;
+  uart::FlushResult flush() override;
+  void set_rx_full_threshold(size_t rx_full_threshold) override;
+  void set_rx_timeout(size_t rx_timeout) override;
+
+  // Scenario configuration - called from generated code
+  void add_injection(const std::vector<uint8_t> &rx_data, uint32_t delay_ms);
+  void add_response(const std::vector<uint8_t> &expect_tx, const std::vector<uint8_t> &inject_rx,
+                    uint32_t delay_ms = 0);
+  void add_periodic_rx(const std::vector<uint8_t> &data, uint32_t interval_ms);
+
+  void start_scenario();
+  void set_auto_start(bool auto_start) { this->auto_start_ = auto_start; }
+  void set_tx_hook(std::function<void(const std::vector<uint8_t> &)> &&cb) { this->tx_hook_ = std::move(cb); }
+  void inject_to_rx_buffer(const std::vector<uint8_t> &data);
+  void inject_to_rx_buffer(const uint8_t *data, size_t len);
+  // Stage bytes for delayed delivery - simulates transport-level latency (e.g., USB packets)
+  void inject_to_rx_buffer_delayed(const std::vector<uint8_t> &data, uint32_t delay_ms);
+
+ protected:
+  void check_logger_conflict() override {}
+  void try_match_response_();
+
+  // Timed injections
+  struct Injection {
+    std::vector<uint8_t> rx_data;
+    uint32_t delay_ms;
+  };
+  std::vector<Injection> injections_;
+  uint32_t injection_index_{0};
+  uint32_t scenario_start_ms_{0};
+  uint32_t cumulative_delay_ms_{0};
+  bool loop_started_{false};
+  bool auto_start_{true};
+  bool scenario_active_{false};
+
+  // TX-triggered responses
+  struct Response {
+    std::vector<uint8_t> expect_tx;
+    std::vector<uint8_t> inject_rx;
+    uint32_t delay_ms;
+    uint32_t last_match_ms{0};
+  };
+  std::vector<Response> responses_;
+  std::vector<uint8_t> tx_buffer_;
+
+  // RX buffer
+  std::deque<uint8_t> rx_buffer_;
+
+  // Periodic RX
+  struct PeriodicRx {
+    std::vector<uint8_t> data;
+    uint32_t interval_ms;
+    uint32_t last_inject_ms{0};
+  };
+  std::vector<PeriodicRx> periodic_rx_;
+
+  // Staged RX - bytes that are pending delivery after a delay
+  // Simulates transport-level latency (e.g., USB packet delivery)
+  struct StagedRx {
+    std::vector<uint8_t> data;
+    uint32_t available_at_ms;  // millis() time when bytes become available
+  };
+  std::deque<StagedRx> staged_rx_;
+
+  // Observability
+  uint32_t tx_count_{0};
+  uint32_t rx_count_{0};
+
+  // Direct TX hook for tests that want to bypass the response-matching logic
+  std::function<void(const std::vector<uint8_t> &)> tx_hook_;
+};
+
+}  // namespace esphome::uart_mock

tests/integration/fixtures/micros_to_millis.yaml

@@ -0,0 +1,61 @@
+esphome:
+  name: micros-to-millis-test
+  platformio_options:
+    build_flags:
+      - "-DDEBUG"
+  on_boot:
+    - lambda: |-
+        using esphome::micros_to_millis;
+        const char *TAG = "MTM";
+        int pass = 0, fail = 0;
+
+        auto check = [&](const char *name, uint64_t us) {
+          uint32_t got = micros_to_millis(us);
+          uint32_t want = (uint32_t)(us / 1000ULL);
+          if (got == want) { pass++; }
+          else { ESP_LOGE(TAG, "%s FAILED: got=%u want=%u", name, got, want); fail++; }
+        };
+
+        // Basic values
+        check("zero", 0);
+        check("below_1ms", 999);
+        check("exactly_1ms", 1000);
+        check("above_1ms", 1001);
+
+        // Shift boundary (1000 = 8 * 125, exercises the >>3 shift)
+        check("shift_7999", 7999);
+        check("shift_8000", 8000);
+        check("shift_8001", 8001);
+
+        // 32-bit boundary
+        check("u32max_minus1", 0xFFFFFFFEULL);
+        check("u32max", 0xFFFFFFFFULL);
+        check("u32max_plus1", 0x100000000ULL);
+
+        // Realistic uptimes
+        check("30_days", 2592000000000ULL);
+        check("1_year", 31536000000000ULL);
+
+        // Carry path: construct x = us>>3 with specific hi/lo that trigger adj overflow
+        { uint64_t x = (603ULL << 32) | 0xFFFFFFFFU; check("carry_603", x << 3); }
+        { uint64_t x = (5000ULL << 32) | 0xFFFFFFFFU; check("carry_5000", x << 3); }
+
+        // Carry boundary: exact transition where adj overflows (hi=1000, R=46)
+        {
+          uint32_t hi = 1000;
+          uint32_t thr = 0xFFFFFFFFU - hi * 46U;
+          uint64_t h = (uint64_t)hi << 32;
+          check("carry_before", (h | (thr - 1)) << 3);
+          check("carry_at", (h | thr) << 3);
+          check("carry_after", (h | (thr + 1)) << 3);
+        }
+
+        // Mod-8 variations (exercises the >>3 truncation)
+        for (int i = 0; i < 8; i++) { check("mod8", 2592000000000ULL + i); }
+
+        if (fail == 0) { ESP_LOGI(TAG, "ALL_PASSED %d tests", pass); }
+        else { ESP_LOGE(TAG, "%d FAILED out of %d", fail, pass + fail); }
+
+host:
+api:
+logger:

tests/integration/fixtures/scheduler_bulk_cleanup.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-bulk-cleanup
 
 external_components:

tests/integration/fixtures/scheduler_defer_cancel.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-defer-cancel
 
 host:

tests/integration/fixtures/scheduler_defer_cancels_regular.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-defer-cancel-regular
 
 host:

tests/integration/fixtures/scheduler_defer_fifo_simple.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-defer-fifo-simple
 
 host:

tests/integration/fixtures/scheduler_defer_stress.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-defer-stress-test
 
 external_components:

tests/integration/fixtures/scheduler_heap_stress.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-heap-stress-test
 
 external_components:

tests/integration/fixtures/scheduler_internal_id_no_collision.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-internal-id-test
   on_boot:
     priority: -100

tests/integration/fixtures/scheduler_null_name.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-null-name
 
 host:

tests/integration/fixtures/scheduler_numeric_id_test.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-numeric-id-test
   on_boot:
     priority: -100

tests/integration/fixtures/scheduler_rapid_cancellation.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: sched-rapid-cancel-test
 
 external_components:

tests/integration/fixtures/scheduler_recursive_timeout.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: sched-recursive-timeout
 
 external_components:

tests/integration/fixtures/scheduler_removed_item_race.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-removed-item-race
 
 host:

tests/integration/fixtures/scheduler_retry_test.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-retry-test
   on_boot:
     priority: -100

tests/integration/fixtures/scheduler_simultaneous_callbacks.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: sched-simul-callbacks-test
 
 external_components:

tests/integration/fixtures/scheduler_string_lifetime.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: scheduler-string-lifetime-test
 
 external_components:

tests/integration/fixtures/scheduler_string_name_stress.yaml

@@ -1,4 +1,5 @@
 esphome:
+  debug_scheduler: true  # Enable scheduler leak detection
   name: sched-string-name-stress
 
 external_components:

tests/integration/fixtures/uart_mock_ld2410.yaml

@@ -0,0 +1,153 @@
+esphome:
+  name: uart-mock-ld2410-test
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy ld2410's DEPENDENCIES = ["uart"]
+# The actual UART bus used is the uart_mock component below
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+uart_mock:
+  id: mock_uart
+  baud_rate: 256000
+  auto_start: false
+  injections:
+    # Phase 1 (t=100ms): Valid LD2410 normal mode data frame - happy path
+    # The buffer is clean at this point, so this frame should parse correctly.
+    # Moving target: 100cm, energy 50
+    # Still target: 120cm, energy 25
+    # Detection distance: 300cm
+    # Target state: 0x03 (moving + still)
+    #
+    # Note: LD2410's two_byte_to_int() uses signed char, so low bytes must be
+    # <=127 to produce correct values. Values >127 wrap negative.
+    #
+    # Frame layout (24 bytes):
+    #   [0-3]  F4 F3 F2 F1 = data frame header
+    #   [4-5]  0D 00       = length 13
+    #   [6]    02          = data type (normal)
+    #   [7]    AA          = data header marker
+    #   [8]    03          = target states (moving+still)
+    #   [9-10] 64 00       = moving distance 100 (0x0064)
+    #   [11]   32          = moving energy 50
+    #   [12-13] 78 00      = still distance 120 (0x0078)
+    #   [14]   19          = still energy 25
+    #   [15-16] 2C 01      = detection distance 300 (0x012C)
+    #   [17]   00          = padding
+    #   [18]   55          = data footer marker
+    #   [19]   00          = CRC/check
+    #   [20-23] F8 F7 F6 F5 = data frame footer
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x0D, 0x00,
+          0x02, 0xAA,
+          0x03,
+          0x64, 0x00,
+          0x32,
+          0x78, 0x00,
+          0x19,
+          0x2C, 0x01,
+          0x00,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+    # Phase 2 (t=200ms): Garbage bytes - corrupt the buffer
+    # These random bytes will accumulate in the LD2410's internal buffer.
+    # No footer will be found, so the buffer just grows.
+    - delay: 100ms
+      inject_rx: [0xDE, 0xAD, 0xBE, 0xEF, 0x00, 0x11, 0x22]
+
+    # Phase 3 (t=300ms): Truncated frame (header + partial data, no footer)
+    # More bytes accumulating in the buffer without a footer match.
+    - delay: 100ms
+      inject_rx: [0xF4, 0xF3, 0xF2, 0xF1, 0x0D, 0x00, 0x02, 0xAA]
+
+    # Phase 4 (t=500ms): Overflow - inject 85 bytes of 0xFF (MAX_LINE_LENGTH=50)
+    # Buffer has 15 bytes from phases 2+3.
+    # Overflow math: need 35 bytes to trigger first overflow (pos 15->49),
+    # then 50 more to trigger second overflow (pos 0->49). Total = 85 bytes.
+    # After two overflows, buffer_pos_ = 0 with a completely clean buffer.
+    # The LD2410 logs "Max command length exceeded" at each overflow.
+    - delay: 200ms
+      inject_rx:
+        [
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+        ]
+
+    # Phase 5 (t=600ms): Valid frame after overflow - recovery test
+    # Buffer was reset by overflow. This valid frame should parse correctly.
+    # Moving target: 50cm, energy 100
+    # Still target: 75cm, energy 80
+    # Detection distance: 127cm
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x0D, 0x00,
+          0x02, 0xAA,
+          0x03,
+          0x32, 0x00,
+          0x64,
+          0x4B, 0x00,
+          0x50,
+          0x7F, 0x00,
+          0x00,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+ld2410:
+  id: ld2410_dev
+  uart_id: mock_uart
+
+sensor:
+  - platform: ld2410
+    ld2410_id: ld2410_dev
+    moving_distance:
+      name: "Moving Distance"
+    still_distance:
+      name: "Still Distance"
+    moving_energy:
+      name: "Moving Energy"
+    still_energy:
+      name: "Still Energy"
+    detection_distance:
+      name: "Detection Distance"
+
+binary_sensor:
+  - platform: ld2410
+    ld2410_id: ld2410_dev
+    has_target:
+      name: "Has Target"
+    has_moving_target:
+      name: "Has Moving Target"
+    has_still_target:
+      name: "Has Still Target"
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    id: start_scenario_btn
+    on_press:
+      - lambda: 'id(mock_uart).start_scenario();'

tests/integration/fixtures/uart_mock_ld2410_engineering.yaml

@@ -0,0 +1,164 @@
+esphome:
+  name: uart-mock-ld2410-eng-test
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy ld2410's DEPENDENCIES = ["uart"]
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+uart_mock:
+  id: mock_uart
+  baud_rate: 256000
+  auto_start: false
+  injections:
+    # Phase 1 (t=100ms): Valid LD2410 engineering mode data frame
+    # Captured from a real Screek Human Presence Sensor 1U with LD2410 firmware 2.4.x
+    #
+    # Engineering mode frame layout (45 bytes):
+    #   [0-3]   F4 F3 F2 F1 = data frame header
+    #   [4-5]   23 00       = length 35
+    #   [6]     01          = data type (engineering mode)
+    #   [7]     AA          = data header marker
+    #   [8]     03          = target states (moving+still)
+    #   [9-10]  1E 00       = moving distance 30 (0x001E)
+    #   [11]    64          = moving energy 100
+    #   [12-13] 1E 00       = still distance 30 (0x001E)
+    #   [14]    64          = still energy 100
+    #   [15-16] 00 00       = detection distance 0
+    #   [17]    08          = max moving distance gate
+    #   [18]    08          = max still distance gate
+    #   [19-27] gate moving energies (gates 0-8)
+    #   [28-36] gate still energies (gates 0-8)
+    #   [37]    57          = light sensor value 87
+    #   [38]    01          = out pin presence (HIGH)
+    #   [39]    55          = data footer marker
+    #   [40]    00          = check
+    #   [41-44] F8 F7 F6 F5 = data frame footer
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x23, 0x00,
+          0x01, 0xAA,
+          0x03,
+          0x1E, 0x00,
+          0x64,
+          0x1E, 0x00,
+          0x64,
+          0x00, 0x00,
+          0x08, 0x08,
+          0x64, 0x41, 0x06, 0x0E, 0x2B, 0x16, 0x03, 0x03, 0x07,
+          0x00, 0x00, 0x64, 0x64, 0x64, 0x64, 0x64, 0x64, 0x64,
+          0x57, 0x01,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+    # Phase 2 (t=200ms): Second engineering mode frame with different values
+    # Real capture: moving at 73cm, still at 30cm, detection at 33cm
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x23, 0x00,
+          0x01, 0xAA,
+          0x03,
+          0x49, 0x00,
+          0x64,
+          0x1E, 0x00,
+          0x64,
+          0x21, 0x00,
+          0x08, 0x08,
+          0x11, 0x64, 0x05, 0x29, 0x39, 0x10, 0x03, 0x11, 0x0E,
+          0x00, 0x00, 0x64, 0x64, 0x64, 0x64, 0x64, 0x64, 0x64,
+          0x57, 0x01,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+    # Phase 3 (t=300ms): Frame with still target at 291cm (multi-byte distance)
+    # This tests the two_byte_to_int function with high byte > 0
+    # Note: low byte 0x2F < 0x80 so it avoids the signed char bug
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x23, 0x00,
+          0x01, 0xAA,
+          0x03,
+          0x2F, 0x00,
+          0x36,
+          0x23, 0x01,
+          0x64,
+          0x21, 0x00,
+          0x08, 0x08,
+          0x2F, 0x36, 0x09, 0x0D, 0x15, 0x0B, 0x06, 0x06, 0x08,
+          0x00, 0x00, 0x64, 0x64, 0x64, 0x64, 0x64, 0x5A, 0x3D,
+          0x57, 0x01,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+ld2410:
+  id: ld2410_dev
+  uart_id: mock_uart
+
+sensor:
+  - platform: ld2410
+    ld2410_id: ld2410_dev
+    moving_distance:
+      name: "Moving Distance"
+    still_distance:
+      name: "Still Distance"
+    moving_energy:
+      name: "Moving Energy"
+    still_energy:
+      name: "Still Energy"
+    detection_distance:
+      name: "Detection Distance"
+    light:
+      name: "Light"
+    g0:
+      move_energy:
+        name: "Gate 0 Move Energy"
+      still_energy:
+        name: "Gate 0 Still Energy"
+    g1:
+      move_energy:
+        name: "Gate 1 Move Energy"
+      still_energy:
+        name: "Gate 1 Still Energy"
+    g2:
+      move_energy:
+        name: "Gate 2 Move Energy"
+      still_energy:
+        name: "Gate 2 Still Energy"
+
+binary_sensor:
+  - platform: ld2410
+    ld2410_id: ld2410_dev
+    has_target:
+      name: "Has Target"
+    has_moving_target:
+      name: "Has Moving Target"
+    has_still_target:
+      name: "Has Still Target"
+    out_pin_presence_status:
+      name: "Out Pin Presence"
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    id: start_scenario_btn
+    on_press:
+      - lambda: 'id(mock_uart).start_scenario();'

tests/integration/fixtures/uart_mock_ld2412.yaml

@@ -0,0 +1,179 @@
+esphome:
+  name: uart-mock-ld2412-test
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy ld2412's DEPENDENCIES = ["uart"]
+# The actual UART bus used is the uart_mock component below
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+uart_mock:
+  id: mock_uart
+  baud_rate: 256000
+  auto_start: false
+  injections:
+    # Phase 1 (t=100ms): Valid LD2412 normal mode data frame - happy path
+    # The buffer is clean at this point, so this frame should parse correctly.
+    # Moving target: 100cm, energy 50
+    # Still target: 120cm, energy 25
+    # Target state: 0x03 (moving + still)
+    # detection_distance = 100 (LD2412 computes from moving target when MOVE_BITMASK set)
+    #
+    # Frame layout (24 bytes):
+    #   [0-3]   F4 F3 F2 F1 = data frame header
+    #   [4-5]   0D 00       = length 13
+    #   [6]     02          = data type (normal)
+    #   [7]     AA          = data header marker
+    #   [8]     03          = target states (moving+still)
+    #   [9-10]  64 00       = moving distance 100 (0x0064)
+    #   [11]    32          = moving energy 50
+    #   [12-13] 78 00       = still distance 120 (0x0078)
+    #   [14]    19          = still energy 25
+    #   [15-16] 64 00       = detect distance bytes (ignored by LD2412 code)
+    #   [17]    00          = padding
+    #   [18]    55          = data footer marker
+    #   [19]    00          = CRC/check
+    #   [20-23] F8 F7 F6 F5 = data frame footer
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x0D, 0x00,
+          0x02, 0xAA,
+          0x03,
+          0x64, 0x00,
+          0x32,
+          0x78, 0x00,
+          0x19,
+          0x64, 0x00,
+          0x00,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+    # Phase 2 (t=300ms): Garbage bytes
+    # LD2412's parser rejects bytes that don't match the frame header at
+    # position 0 (must start with F4 or FD), so buffer stays empty.
+    - delay: 200ms
+      inject_rx: [0xDE, 0xAD, 0xBE, 0xEF, 0x00, 0x11, 0x22]
+
+    # Phase 3 (t=400ms): Truncated frame (header + partial data, no footer)
+    # Starts with valid data frame header so parser accepts it.
+    # After this, buffer_pos_ = 8.
+    - delay: 100ms
+      inject_rx: [0xF4, 0xF3, 0xF2, 0xF1, 0x0D, 0x00, 0x02, 0xAA]
+
+    # Phase 4 (t=600ms): Overflow - inject 60 bytes of 0xFF (MAX_LINE_LENGTH=54)
+    # Buffer has 8 bytes from phase 3 (garbage in phase 2 was rejected).
+    # Overflow math: buffer_pos_ starts at 8, overflow triggers when
+    # buffer_pos_ reaches 53 (MAX_LINE_LENGTH - 1). Need 45 more bytes to
+    # fill positions 8-52, then byte 46 triggers overflow. After overflow,
+    # buffer_pos_ = 0 and remaining 0xFF bytes are rejected (don't match header).
+    - delay: 200ms
+      inject_rx:
+        [
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+        ]
+
+    # Phase 5 (t=700ms): Valid frame after overflow - recovery test
+    # Buffer was reset by overflow. This valid frame should parse correctly.
+    # Moving target: 50cm, energy 100
+    # Still target: 75cm, energy 80
+    # detection_distance = 50 (moving target distance, since MOVE_BITMASK set)
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x0D, 0x00,
+          0x02, 0xAA,
+          0x03,
+          0x32, 0x00,
+          0x64,
+          0x4B, 0x00,
+          0x50,
+          0x32, 0x00,
+          0x00,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+ld2412:
+  id: ld2412_dev
+  uart_id: mock_uart
+
+sensor:
+  - platform: ld2412
+    ld2412_id: ld2412_dev
+    moving_distance:
+      name: "Moving Distance"
+      filters:
+        - timeout:
+            timeout: 50ms
+            value: last
+        - throttle_with_priority: 50ms
+    still_distance:
+      name: "Still Distance"
+      filters:
+        - timeout:
+            timeout: 50ms
+            value: last
+        - throttle_with_priority: 50ms
+    moving_energy:
+      name: "Moving Energy"
+      filters:
+        - timeout:
+            timeout: 50ms
+            value: last
+        - throttle_with_priority: 50ms
+    still_energy:
+      name: "Still Energy"
+      filters:
+        - timeout:
+            timeout: 50ms
+            value: last
+        - throttle_with_priority: 50ms
+    detection_distance:
+      name: "Detection Distance"
+      filters:
+        - timeout:
+            timeout: 50ms
+            value: last
+        - throttle_with_priority: 50ms
+
+binary_sensor:
+  - platform: ld2412
+    ld2412_id: ld2412_dev
+    has_target:
+      name: "Has Target"
+      filters:
+        - settle: 50ms
+    has_moving_target:
+      name: "Has Moving Target"
+      filters:
+        - settle: 50ms
+    has_still_target:
+      name: "Has Still Target"
+      filters:
+        - settle: 50ms
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    id: start_scenario_btn
+    on_press:
+      - lambda: 'id(mock_uart).start_scenario();'

tests/integration/fixtures/uart_mock_ld2412_engineering.yaml

@@ -0,0 +1,182 @@
+esphome:
+  name: uart-mock-ld2412-eng-test
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy ld2412's DEPENDENCIES = ["uart"]
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+uart_mock:
+  id: mock_uart
+  baud_rate: 256000
+  auto_start: false
+  injections:
+    # Phase 1 (t=100ms): Valid LD2412 engineering mode data frame
+    #
+    # Engineering mode frame layout (52 bytes):
+    #   [0-3]   F4 F3 F2 F1 = data frame header
+    #   [4-5]   2A 00       = length 42
+    #   [6]     01          = data type (engineering mode)
+    #   [7]     AA          = data header marker
+    #   [8]     03          = target states (moving+still)
+    #   [9-10]  1E 00       = moving distance 30 (0x001E)
+    #   [11]    64          = moving energy 100
+    #   [12-13] 1E 00       = still distance 30 (0x001E)
+    #   [14]    64          = still energy 100
+    #   [15-16] 00 00       = detection distance bytes (ignored)
+    #   [17-30] gate moving energies (14 gates)
+    #   [31-44] gate still energies (14 gates)
+    #   [45]    57          = light sensor value 87
+    #   [46]    55          = data footer marker
+    #   [47]    00          = check
+    #   [48-51] F8 F7 F6 F5 = data frame footer
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x2A, 0x00,
+          0x01, 0xAA,
+          0x03,
+          0x1E, 0x00,
+          0x64,
+          0x1E, 0x00,
+          0x64,
+          0x00, 0x00,
+          0x64, 0x41, 0x06, 0x0E, 0x2B, 0x16, 0x03, 0x03, 0x07, 0x05, 0x09, 0x08, 0x07, 0x06,
+          0x00, 0x00, 0x64, 0x64, 0x64, 0x64, 0x64, 0x64, 0x64, 0x50, 0x40, 0x30, 0x20, 0x10,
+          0x57,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+    # Phase 2 (t=200ms): Second engineering mode frame with different values
+    # Moving at 73cm, still at 30cm
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x2A, 0x00,
+          0x01, 0xAA,
+          0x03,
+          0x49, 0x00,
+          0x64,
+          0x1E, 0x00,
+          0x64,
+          0x21, 0x00,
+          0x11, 0x64, 0x05, 0x29, 0x39, 0x10, 0x03, 0x11, 0x0E, 0x08, 0x06, 0x04, 0x03, 0x02,
+          0x00, 0x00, 0x64, 0x64, 0x64, 0x64, 0x64, 0x64, 0x64, 0x50, 0x40, 0x30, 0x20, 0x10,
+          0x57,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+    # Phase 3 (t=300ms): Frame with still target at 291cm (multi-byte distance)
+    # This tests encode_uint16 with high byte > 0
+    # Target state: 0x02 (still only) -> detection_distance = still distance = 291
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x2A, 0x00,
+          0x01, 0xAA,
+          0x02,
+          0x2F, 0x00,
+          0x36,
+          0x23, 0x01,
+          0x64,
+          0x21, 0x00,
+          0x2F, 0x36, 0x09, 0x0D, 0x15, 0x0B, 0x06, 0x06, 0x08, 0x09, 0x08, 0x07, 0x06, 0x05,
+          0x00, 0x00, 0x64, 0x64, 0x64, 0x64, 0x64, 0x5A, 0x3D, 0x30, 0x20, 0x10, 0x08, 0x04,
+          0x57,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+# Common filter definitions
+.sensor_filters: &sensor_filters
+  filters:
+    - timeout:
+        timeout: 50ms
+        value: last
+    - throttle_with_priority: 50ms
+
+.binary_filters: &binary_filters
+  filters:
+    - settle: 50ms
+
+ld2412:
+  id: ld2412_dev
+  uart_id: mock_uart
+
+sensor:
+  - platform: ld2412
+    ld2412_id: ld2412_dev
+    moving_distance:
+      name: "Moving Distance"
+      <<: *sensor_filters
+    still_distance:
+      name: "Still Distance"
+      <<: *sensor_filters
+    moving_energy:
+      name: "Moving Energy"
+      <<: *sensor_filters
+    still_energy:
+      name: "Still Energy"
+      <<: *sensor_filters
+    detection_distance:
+      name: "Detection Distance"
+      <<: *sensor_filters
+    light:
+      name: "Light"
+      <<: *sensor_filters
+    gate_0:
+      move_energy:
+        name: "Gate 0 Move Energy"
+        <<: *sensor_filters
+      still_energy:
+        name: "Gate 0 Still Energy"
+        <<: *sensor_filters
+    gate_1:
+      move_energy:
+        name: "Gate 1 Move Energy"
+        <<: *sensor_filters
+      still_energy:
+        name: "Gate 1 Still Energy"
+        <<: *sensor_filters
+    gate_2:
+      move_energy:
+        name: "Gate 2 Move Energy"
+        <<: *sensor_filters
+      still_energy:
+        name: "Gate 2 Still Energy"
+        <<: *sensor_filters
+
+binary_sensor:
+  - platform: ld2412
+    ld2412_id: ld2412_dev
+    has_target:
+      name: "Has Target"
+      <<: *binary_filters
+    has_moving_target:
+      name: "Has Moving Target"
+      <<: *binary_filters
+    has_still_target:
+      name: "Has Still Target"
+      <<: *binary_filters
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    id: start_scenario_btn
+    on_press:
+      - lambda: 'id(mock_uart).start_scenario();'

tests/integration/fixtures/uart_mock_ld2412_engineering_truncated.yaml

@@ -0,0 +1,167 @@
+esphome:
+  name: uart-mock-ld2412-eng-trunc
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy ld2412's DEPENDENCIES = ["uart"]
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+uart_mock:
+  id: mock_uart
+  baud_rate: 256000
+  auto_start: false
+  injections:
+    # Phase 1 (t=100ms): Valid engineering mode frame (52 bytes, buffer_pos_=52)
+    # Establishes baseline: gate_0_move=100, light=87
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x2A, 0x00,
+          0x01, 0xAA,
+          0x03,
+          0x1E, 0x00,
+          0x64,
+          0x1E, 0x00,
+          0x64,
+          0x00, 0x00,
+          0x64, 0x41, 0x06, 0x0E, 0x2B, 0x16, 0x03, 0x03, 0x07, 0x05, 0x09, 0x08, 0x07, 0x06,
+          0x00, 0x00, 0x64, 0x64, 0x64, 0x64, 0x64, 0x64, 0x64, 0x50, 0x40, 0x30, 0x20, 0x10,
+          0x57,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+    # Phase 2 (t=200ms): Truncated engineering mode frame (24 bytes, buffer_pos_=24)
+    # This frame has data_type=0x01 (engineering) but only enough data for the
+    # basic target fields, not the gate energies or light sensor.
+    # buffer_pos_=24 passes the old check (>= 12) but fails the new check (< 46).
+    # Without the fix, indices 17-45 would read stale buffer data from Phase 1.
+    #
+    # Layout (24 bytes):
+    #   [0-3]   F4 F3 F2 F1 = data frame header
+    #   [4-5]   0E 00       = length 14
+    #   [6]     01          = data type (engineering mode)
+    #   [7]     AA          = data header marker
+    #   [8]     03          = target states (moving+still)
+    #   [9-10]  1E 00       = moving distance 30
+    #   [11]    50          = moving energy 80
+    #   [12-13] 1E 00       = still distance 30
+    #   [14]    50          = still energy 80
+    #   [15-16] FF FF       = garbage detection distance bytes
+    #   [17]    FF          = padding (would be gate data in full frame)
+    #   [18]    55          = data footer marker (at buffer_pos_ - 6)
+    #   [19]    00          = check byte
+    #   [20-23] F8 F7 F6 F5 = data frame footer
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x0E, 0x00,
+          0x01, 0xAA,
+          0x03,
+          0x1E, 0x00,
+          0x50,
+          0x1E, 0x00,
+          0x50,
+          0xFF, 0xFF,
+          0xFF,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+    # Phase 3 (t=300ms): Valid recovery frame with different values
+    # gate_0_move=50, light=42 — proves component recovered
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x2A, 0x00,
+          0x01, 0xAA,
+          0x03,
+          0x1E, 0x00,
+          0x64,
+          0x1E, 0x00,
+          0x64,
+          0x00, 0x00,
+          0x32, 0x20, 0x06, 0x0E, 0x2B, 0x16, 0x03, 0x03, 0x07, 0x05, 0x09, 0x08, 0x07, 0x06,
+          0x00, 0x00, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x28, 0x20, 0x18, 0x10, 0x08,
+          0x2A,
+          0x55, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+# Common filter definitions
+.sensor_filters: &sensor_filters
+  filters:
+    - timeout:
+        timeout: 50ms
+        value: last
+    - throttle_with_priority: 50ms
+
+.binary_filters: &binary_filters
+  filters:
+    - settle: 50ms
+
+ld2412:
+  id: ld2412_dev
+  uart_id: mock_uart
+
+sensor:
+  - platform: ld2412
+    ld2412_id: ld2412_dev
+    moving_distance:
+      name: "Moving Distance"
+      <<: *sensor_filters
+    still_distance:
+      name: "Still Distance"
+      <<: *sensor_filters
+    moving_energy:
+      name: "Moving Energy"
+      <<: *sensor_filters
+    still_energy:
+      name: "Still Energy"
+      <<: *sensor_filters
+    detection_distance:
+      name: "Detection Distance"
+      <<: *sensor_filters
+    light:
+      name: "Light"
+      <<: *sensor_filters
+    gate_0:
+      move_energy:
+        name: "Gate 0 Move Energy"
+        <<: *sensor_filters
+      still_energy:
+        name: "Gate 0 Still Energy"
+        <<: *sensor_filters
+
+binary_sensor:
+  - platform: ld2412
+    ld2412_id: ld2412_dev
+    has_target:
+      name: "Has Target"
+      <<: *binary_filters
+    has_moving_target:
+      name: "Has Moving Target"
+      <<: *binary_filters
+    has_still_target:
+      name: "Has Still Target"
+      <<: *binary_filters
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    id: start_scenario_btn
+    on_press:
+      - lambda: 'id(mock_uart).start_scenario();'

tests/integration/fixtures/uart_mock_ld2420.yaml

@@ -0,0 +1,187 @@
+esphome:
+  name: uart-mock-ld2420-test
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy ld2420's DEPENDENCIES = ["uart"]
+# The actual UART bus used is the uart_mock component below
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+uart_mock:
+  id: mock_uart
+  baud_rate: 115200
+  auto_start: false
+  responses:
+    # Version-specific response: match the complete firmware version command TX.
+    # CMD_READ_VERSION (0x0000) TX = FD FC FB FA 02 00 00 00 04 03 02 01
+    # Returns "v2.0.0" → get_firmware_int = 200 >= 154 → energy mode
+    #
+    # Response layout:
+    #   [0-3]   FD FC FB FA = header
+    #   [4-5]   0C 00       = length 12
+    #   [6]     00          = cmd (CMD_READ_VERSION)
+    #   [7]     01          = status (ACK)
+    #   [8-9]   00 00       = error = 0
+    #   [10]    06          = ver_len = 6
+    #   [11]    00          = padding
+    #   [12-17] "v2.0.0"   = version string
+    #   [18-21] 04 03 02 01 = footer
+    - expect_tx:
+        [0xFD, 0xFC, 0xFB, 0xFA, 0x02, 0x00, 0x00, 0x00, 0x04, 0x03, 0x02, 0x01]
+      inject_rx:
+        [
+          0xFD, 0xFC, 0xFB, 0xFA,
+          0x0C, 0x00,
+          0x00, 0x01,
+          0x00, 0x00,
+          0x06, 0x00,
+          0x76, 0x32, 0x2E, 0x30, 0x2E, 0x30,
+          0x04, 0x03, 0x02, 0x01,
+        ]
+
+    # Catch-all response: match any command footer (04 03 02 01).
+    # Returns a generic ACK with cmd=0xFF (CMD_ENABLE_CONF case in switch).
+    # All commands get unblocked via cmd_reply_.ack = true.
+    # Data fields stay zeroed (min_gate=0, max_gate=0, timeout=0, thresholds=0).
+    #
+    # Response layout:
+    #   [0-3]  FD FC FB FA = header
+    #   [4-5]  04 00       = length 4
+    #   [6]    FF          = cmd (handled as CMD_ENABLE_CONF)
+    #   [7]    01          = status (ACK)
+    #   [8-9]  00 00       = error = 0
+    #   [10-13] 04 03 02 01 = footer
+    - expect_tx: [0x04, 0x03, 0x02, 0x01]
+      inject_rx:
+        [
+          0xFD, 0xFC, 0xFB, 0xFA,
+          0x04, 0x00,
+          0xFF, 0x01,
+          0x00, 0x00,
+          0x04, 0x03, 0x02, 0x01,
+        ]
+
+  injections:
+    # Phase 1 (t=100ms): Valid LD2420 energy mode data frame - happy path
+    # Buffer is clean (buffer_pos_=0). This frame should parse correctly.
+    # Presence: 1 (target detected), Distance: 100cm, Gate energies: all 0
+    #
+    # Energy frame layout (45 bytes):
+    #   [0-3]   F4 F3 F2 F1 = energy frame header
+    #   [4-5]   23 00       = length 35 (1+2+32)
+    #   [6]     01          = presence (1 = target)
+    #   [7-8]   64 00       = distance 100 (uint16_t LE)
+    #   [9-40]  00 00 x16   = 16 gate energies (uint16_t LE each)
+    #   [41-44] F8 F7 F6 F5 = energy frame footer
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x23, 0x00,
+          0x01,
+          0x64, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+    # Phase 2 (t=300ms): Garbage bytes
+    # LD2420's readline_ does NOT check frame headers at position 0 (unlike LD2412),
+    # so these bytes accumulate in the buffer. buffer_pos_ goes from 0 to 7.
+    - delay: 200ms
+      inject_rx: [0xDE, 0xAD, 0xBE, 0xEF, 0x00, 0x11, 0x22]
+
+    # Phase 3 (t=400ms): Truncated energy frame WITH footer (13 bytes)
+    # This tests PR #14458 bug #3: missing length validation in handle_energy_mode_.
+    # The 7 garbage bytes from Phase 2 are still in the buffer (buffer_pos_=7).
+    # These 13 bytes are appended at positions 7-19 (buffer_pos_=20).
+    # Energy footer at positions 16-19 triggers handle_energy_mode_(buffer, 20).
+    #
+    # Pre-fix: handle_energy_mode_ reads 32 bytes of gate energy from buffer[9:40],
+    #          which is past the 20 actual bytes. Reads uninitialized data.
+    #          No "Energy frame too short" warning exists.
+    # Post-fix: len=20 < 41 → logs "Energy frame too short: 20 bytes", returns early.
+    #
+    # Frame: header + length + presence + distance + footer (no gate data)
+    - delay: 100ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x23, 0x00,
+          0x01,
+          0x64, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+    # Phase 4 (t=600ms): Overflow - inject 50 bytes of 0xFF (MAX_LINE_LENGTH=50)
+    # After Phase 3, buffer_pos_=0 (reset after energy footer detection).
+    # 49 bytes fill positions 0-48 (buffer_pos_=49), 50th byte triggers overflow.
+    # Logs "Max command length exceeded; ignoring", buffer_pos_=0.
+    - delay: 200ms
+      inject_rx:
+        [
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+        ]
+
+    # Phase 5 (t=1500ms): Valid frame after overflow - recovery test
+    # Buffer was reset by overflow. This valid frame should parse correctly.
+    # Presence: 1 (target), Distance: 50cm
+    # Delay=900ms ensures >1000ms gap from Phase 1 for REFRESH_RATE_MS throttle.
+    - delay: 900ms
+      inject_rx:
+        [
+          0xF4, 0xF3, 0xF2, 0xF1,
+          0x23, 0x00,
+          0x01,
+          0x32, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0xF8, 0xF7, 0xF6, 0xF5,
+        ]
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    on_press:
+      - lambda: 'id(mock_uart).start_scenario();'
+
+ld2420:
+  id: ld2420_dev
+  uart_id: mock_uart
+
+sensor:
+  - platform: ld2420
+    ld2420_id: ld2420_dev
+    moving_distance:
+      name: "Moving Distance"
+      filters:
+        - timeout:
+            timeout: 50ms
+            value: last
+        - throttle_with_priority: 50ms
+
+binary_sensor:
+  - platform: ld2420
+    ld2420_id: ld2420_dev
+    has_target:
+      name: "Has Target"
+      filters:
+        - settle: 50ms

tests/integration/fixtures/uart_mock_ld2420_simple.yaml

@@ -0,0 +1,141 @@
+esphome:
+  name: uart-mock-ld2420-simple-test
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy ld2420's DEPENDENCIES = ["uart"]
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+uart_mock:
+  id: mock_uart
+  baud_rate: 115200
+  auto_start: false
+  responses:
+    # Catch-all response only (no version-specific response).
+    # Without a version response, firmware_ver_ stays at default "v0.0.0".
+    # get_firmware_int("v0.0.0") = 0 < 154 → simple mode (CMD_SYSTEM_MODE_SIMPLE).
+    - expect_tx: [0x04, 0x03, 0x02, 0x01]
+      inject_rx:
+        [
+          0xFD, 0xFC, 0xFB, 0xFA,
+          0x04, 0x00,
+          0xFF, 0x01,
+          0x00, 0x00,
+          0x04, 0x03, 0x02, 0x01,
+        ]
+
+  injections:
+    # Phase 1 (t=100ms): Valid simple mode text frame - happy path
+    # "ON Range 0100\r\n" → presence=true, distance=100
+    # Simple mode frames end with \r\n (0x0D 0x0A), triggering handle_simple_mode_.
+    - delay: 100ms
+      inject_rx:
+        [
+          0x4F, 0x4E, 0x20, 0x52, 0x61, 0x6E, 0x67, 0x65, 0x20,
+          0x30, 0x31, 0x30, 0x30,
+          0x0D, 0x0A,
+        ]
+
+    # Phase 2 (t=300ms): Garbage bytes
+    # LD2420's readline_ stores all bytes regardless of header. buffer_pos_ = 7.
+    - delay: 200ms
+      inject_rx: [0xDE, 0xAD, 0xBE, 0xEF, 0x00, 0x11, 0x22]
+
+    # Phase 3 (t=500ms): Overflow - inject 50 bytes of 0xFF (MAX_LINE_LENGTH=50)
+    # buffer_pos_ starts at 7 (from Phase 2 garbage).
+    # Positions 7-48 fill (42 bytes), byte 43 triggers overflow (buffer_pos_=49).
+    # After overflow: buffer_pos_=0, remaining 7 bytes fill positions 0-6.
+    # Final buffer_pos_ = 7.
+    - delay: 200ms
+      inject_rx:
+        [
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+        ]
+
+    # Phase 4 (t=1400ms): Recovery after overflow
+    # buffer_pos_ = 7 (from overflow remainder). These 15 bytes fill positions 7-21.
+    # At position 21 (0x0A), \r\n detected → handle_simple_mode_(buffer, 22).
+    # Parser skips 0xFF bytes at positions 0-6, finds "ON" at positions 7-8,
+    # parses digits "0050" → distance=50.
+    # Delay=900ms ensures >1000ms gap from Phase 1 for REFRESH_RATE_MS throttle.
+    - delay: 900ms
+      inject_rx:
+        [
+          0x4F, 0x4E, 0x20, 0x52, 0x61, 0x6E, 0x67, 0x65, 0x20,
+          0x30, 0x30, 0x35, 0x30,
+          0x0D, 0x0A,
+        ]
+
+    # Phase 5 (t=2500ms): 16-digit distance - tests PR #14458 bug #1
+    # "ON Range 0000000000000000\r\n" has 16 digit characters.
+    # handle_simple_mode_ outbuf is 16 bytes, can hold 15 digits (index 0-14).
+    #
+    # Pre-fix: At the 16th digit, index=15, (index < bufsize-1) is false.
+    #          The digit branch doesn't increment pos. The else branch is skipped.
+    #          pos stays at the 16th digit FOREVER → INFINITE LOOP.
+    #          The binary hangs, no more state updates, test times out.
+    # Post-fix: pos always increments (moved outside digit branch).
+    #          16th digit skipped, loop continues to \r\n. distance=0.
+    - delay: 1100ms
+      inject_rx:
+        [
+          0x4F, 0x4E, 0x20, 0x52, 0x61, 0x6E, 0x67, 0x65, 0x20,
+          0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
+          0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
+          0x0D, 0x0A,
+        ]
+
+    # Phase 6 (t=3700ms): Post-bug-trigger recovery
+    # If Phase 5 didn't hang, this frame should parse correctly.
+    # "ON Range 0025\r\n" → distance=25
+    # Delay=1200ms ensures >1000ms gap from Phase 5 for throttle.
+    - delay: 1200ms
+      inject_rx:
+        [
+          0x4F, 0x4E, 0x20, 0x52, 0x61, 0x6E, 0x67, 0x65, 0x20,
+          0x30, 0x30, 0x32, 0x35,
+          0x0D, 0x0A,
+        ]
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    on_press:
+      - lambda: 'id(mock_uart).start_scenario();'
+
+ld2420:
+  id: ld2420_dev
+  uart_id: mock_uart
+
+sensor:
+  - platform: ld2420
+    ld2420_id: ld2420_dev
+    moving_distance:
+      name: "Moving Distance"
+      filters:
+        - timeout:
+            timeout: 50ms
+            value: last
+        - throttle_with_priority: 50ms
+
+binary_sensor:
+  - platform: ld2420
+    ld2420_id: ld2420_dev
+    has_target:
+      name: "Has Target"
+      filters:
+        - settle: 50ms

tests/integration/fixtures/uart_mock_ld2450.yaml

@@ -0,0 +1,221 @@
+esphome:
+  name: uart-mock-ld2450-test
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy ld2450's DEPENDENCIES = ["uart"]
+# The actual UART bus used is the uart_mock component below
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+uart_mock:
+  id: mock_uart
+  baud_rate: 256000
+  auto_start: false
+  responses:
+    # Catch-all response: match any command footer (04 03 02 01).
+    # Returns a generic ACK to unblock setup commands.
+    #
+    # Response layout:
+    #   [0-3]  FD FC FB FA = header
+    #   [4-5]  04 00       = length 4
+    #   [6]    FF          = cmd (handled as CMD_ENABLE_CONF)
+    #   [7]    01          = status (ACK)
+    #   [8-9]  00 00       = error = 0
+    #   [10-13] 04 03 02 01 = footer
+    - expect_tx: [0x04, 0x03, 0x02, 0x01]
+      inject_rx:
+        [
+          0xFD, 0xFC, 0xFB, 0xFA,
+          0x04, 0x00,
+          0xFF, 0x01,
+          0x00, 0x00,
+          0x04, 0x03, 0x02, 0x01,
+        ]
+
+  injections:
+    # Phase 1 (t=100ms): Valid LD2450 periodic data frame - happy path
+    # The buffer is clean at this point, so this frame should parse correctly.
+    #
+    # Target 1: X=-500mm, Y=1000mm, Speed=-50mm/s (approaching), Res=320mm
+    #   X: magnitude=500 (0x01F4), negative → high=0x01, low=0xF4
+    #   Y: magnitude=1000 (0x03E8), positive → high=0x83, low=0xE8
+    #   Speed: raw=5, negative (approaching) → high=0x00, low=0x05, decoded=-50mm/s
+    #   Resolution: 320 → low=0x40, high=0x01
+    #   Distance: sqrt(500²+1000²) = sqrt(1250000) ≈ 1118mm
+    #
+    # Target 2: X=200mm, Y=500mm, Speed=0 (stationary), Res=100mm
+    #   X: magnitude=200 (0x00C8), positive → high=0x80, low=0xC8
+    #   Y: magnitude=500 (0x01F4), positive → high=0x81, low=0xF4
+    #   Speed: 0 → 0x00, 0x00
+    #   Resolution: 100 → low=0x64, high=0x00
+    #   Distance: sqrt(200²+500²) = sqrt(290000) ≈ 538mm
+    #
+    # Target 3: No target (all zeros)
+    #   Distance: 0 → sensors publish unknown/NaN
+    #
+    # Counts: target_count=2, moving_target_count=1, still_target_count=1
+    #
+    # Frame layout (30 bytes):
+    #   [0-3]   AA FF 03 00 = periodic data header
+    #   [4-11]  Target 1 (8 bytes): X_L X_H Y_L Y_H SPD_L SPD_H RES_L RES_H
+    #   [12-19] Target 2 (8 bytes)
+    #   [20-27] Target 3 (8 bytes)
+    #   [28-29] 55 CC = periodic data footer
+    - delay: 100ms
+      inject_rx:
+        [
+          0xAA, 0xFF, 0x03, 0x00,
+          0xF4, 0x01, 0xE8, 0x83, 0x05, 0x00, 0x40, 0x01,
+          0xC8, 0x80, 0xF4, 0x81, 0x00, 0x00, 0x64, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0x55, 0xCC,
+        ]
+
+    # Phase 2 (t=300ms): Garbage bytes
+    # LD2450's readline_ does NOT reject bytes at position 0 (unlike LD2412),
+    # so these bytes accumulate in the buffer. buffer_pos_ goes from 0 to 7.
+    - delay: 200ms
+      inject_rx: [0xDE, 0xAD, 0xBE, 0xEF, 0x00, 0x11, 0x22]
+
+    # Phase 3 (t=400ms): Truncated frame (header + partial data, no footer)
+    # More bytes accumulating in the buffer without a footer match.
+    # After this, buffer_pos_ = 7 + 8 = 15.
+    - delay: 100ms
+      inject_rx: [0xAA, 0xFF, 0x03, 0x00, 0x01, 0x02, 0x03, 0x04]
+
+    # Phase 4 (t=600ms): Overflow - inject 75 bytes of 0xFF (MAX_LINE_LENGTH=45)
+    # Buffer has 15 bytes from phases 2+3.
+    # readline_() stores bytes while buffer_pos_ < 44. When buffer_pos_ == 44,
+    # the next byte triggers overflow: logs warning, resets buffer_pos_ to 0,
+    # and discards that byte.
+    #
+    # First overflow: 29 bytes fill positions 15-43 (buffer_pos_=44), byte 30
+    #   triggers overflow (discarded). Total consumed: 30 bytes.
+    # Second overflow: 44 bytes fill positions 0-43 (buffer_pos_=44), byte 45
+    #   triggers overflow (discarded). Total consumed: 30+45 = 75 bytes.
+    # After both overflows, buffer_pos_ = 0 (clean state for recovery frame).
+    - delay: 200ms
+      inject_rx:
+        [
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+          0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+        ]
+
+    # Phase 5 (t=700ms): Valid frame after overflow - recovery test
+    # Buffer was reset by overflow. This valid frame should parse correctly.
+    #
+    # Target 1: X=300mm, Y=400mm, Speed=30mm/s (moving away), Res=100mm
+    #   X: magnitude=300 (0x012C), positive → high=0x81, low=0x2C
+    #   Y: magnitude=400 (0x0190), positive → high=0x81, low=0x90
+    #   Speed: raw=3, positive (moving away) → high=0x80, low=0x03, decoded=30mm/s
+    #   Resolution: 100 → low=0x64, high=0x00
+    #   Distance: sqrt(300²+400²) = 500mm
+    #
+    # Target 2 & 3: No target (all zeros)
+    # Counts: target_count=1, moving_target_count=1, still_target_count=0
+    - delay: 100ms
+      inject_rx:
+        [
+          0xAA, 0xFF, 0x03, 0x00,
+          0x2C, 0x81, 0x90, 0x81, 0x03, 0x80, 0x64, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+          0x55, 0xCC,
+        ]
+
+ld2450:
+  id: ld2450_dev
+  uart_id: mock_uart
+
+sensor:
+  - platform: ld2450
+    ld2450_id: ld2450_dev
+    target_count:
+      name: "Target Count"
+      filters: &sensor_filters
+        - timeout:
+            timeout: 50ms
+            value: last
+        - throttle_with_priority: 50ms
+    still_target_count:
+      name: "Still Target Count"
+      filters: *sensor_filters
+    moving_target_count:
+      name: "Moving Target Count"
+      filters: *sensor_filters
+    target_1:
+      x:
+        name: "Target 1 X"
+        filters: *sensor_filters
+      y:
+        name: "Target 1 Y"
+        filters: *sensor_filters
+      speed:
+        name: "Target 1 Speed"
+        filters: *sensor_filters
+      distance:
+        name: "Target 1 Distance"
+        filters: *sensor_filters
+      resolution:
+        name: "Target 1 Resolution"
+        filters: *sensor_filters
+      angle:
+        name: "Target 1 Angle"
+        filters: *sensor_filters
+    target_2:
+      x:
+        name: "Target 2 X"
+        filters: *sensor_filters
+      y:
+        name: "Target 2 Y"
+        filters: *sensor_filters
+      speed:
+        name: "Target 2 Speed"
+        filters: *sensor_filters
+      distance:
+        name: "Target 2 Distance"
+        filters: *sensor_filters
+
+binary_sensor:
+  - platform: ld2450
+    ld2450_id: ld2450_dev
+    has_target:
+      name: "Has Target"
+      filters: &binary_sensor_filters
+        - settle: 50ms
+    has_moving_target:
+      name: "Has Moving Target"
+      filters: *binary_sensor_filters
+    has_still_target:
+      name: "Has Still Target"
+      filters: *binary_sensor_filters
+
+text_sensor:
+  - platform: ld2450
+    ld2450_id: ld2450_dev
+    target_1:
+      direction:
+        name: "Target 1 Direction"
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    id: start_scenario_btn
+    on_press:
+      - lambda: 'id(mock_uart).start_scenario();'

tests/integration/fixtures/uart_mock_modbus.yaml

@@ -0,0 +1,92 @@
+esphome:
+  name: uart-mock-modbus-test
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy modbus's DEPENDENCIES = ["uart"]
+# The actual UART bus used is the uart_mock component below
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+uart_mock:
+  - id: virtual_uart_dev
+    baud_rate: 9600
+    rx_full_threshold: 120
+    rx_timeout: 2
+    auto_start: false
+    debug:
+    responses:
+      - expect_tx: [0x01, 0x03, 0x00, 0x03, 0x00, 0x01, 0x74, 0x0A] # Read holding register 3 on device 1 (basic_register)
+        inject_rx: [0x01, 0x03, 0x02, 0x01, 0x03, 0xF9, 0xD5] # Return value 0x0103 (hex) = 259 (dec)
+      - expect_tx: [0x01, 0x03, 0x00, 0x05, 0x00, 0x01, 0x94, 0x0B] # Read holding register 5 on device 1 (delayed_response)
+        delay: 100ms # Shorter than modbus send_wait_time of 200ms, should succeed
+        inject_rx: [0x01, 0x03, 0x02, 0x00, 0xFF, 0xF8, 0x04] # Return value 0x00FF (hex) = 255 (dec)
+      - expect_tx: [0x02, 0x03, 0x00, 0x07, 0x00, 0x01, 0x35, 0xF8] # Read holding register 7 on device 2 (late_response)
+        delay: 300ms # Longer than modbus send_wait_time of 200ms, should cause timeout
+        inject_rx: [0x02, 0x03, 0x02, 0x00, 0xF0, 0xFC, 0x00] # Return value 0x00F0 (hex) = 240 (dec)
+      - expect_tx: [0x03, 0x03, 0x00, 0x09, 0x00, 0x01, 0x55, 0xEA] # Read holding register 9 on device 3 (no_response)
+        inject_rx: [] # No response, should cause timeout
+      - expect_tx: [0x01, 0x03, 0x00, 0x0A, 0x00, 0x01, 0xA4, 0x08] # Read holding register A on device 1 (exception_response)
+        inject_rx: [0x01, 0x83, 0x02, 0xC0, 0xF1] # Exception response with code 2 (illegal data address)
+
+modbus:
+  uart_id: virtual_uart_dev
+  send_wait_time: 200ms
+  turnaround_time: 10ms
+
+modbus_controller:
+  - address: 1
+    id: modbus_controller_ok
+    max_cmd_retries: 0
+    update_interval: 1s
+  - address: 2
+    id: modbus_controller_slow
+    max_cmd_retries: 0
+    update_interval: 1s
+  - address: 3
+    id: modbus_controller_offline
+    max_cmd_retries: 0
+    update_interval: 1s
+
+sensor:
+  - platform: modbus_controller
+    name: "basic_register"
+    address: 0x03
+    register_type: holding
+    modbus_controller_id: modbus_controller_ok
+  - platform: modbus_controller
+    name: "delayed_response"
+    address: 0x05
+    register_type: holding
+    modbus_controller_id: modbus_controller_ok
+  - platform: modbus_controller
+    name: "late_response"
+    address: 0x07
+    register_type: holding
+    modbus_controller_id: modbus_controller_slow
+  - platform: modbus_controller
+    name: "no_response"
+    address: 0x09
+    register_type: holding
+    modbus_controller_id: modbus_controller_offline
+  - platform: modbus_controller
+    name: "exception_response"
+    address: 0x0A
+    register_type: holding
+    modbus_controller_id: modbus_controller_ok
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    id: start_scenario_btn
+    on_press:
+      - lambda: 'id(virtual_uart_dev).start_scenario();'

tests/integration/fixtures/uart_mock_modbus_no_threshold.yaml

@@ -0,0 +1,64 @@
+esphome:
+  name: uart-mock-modbus-no-thresh
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy modbus's DEPENDENCIES = ["uart"]
+# The actual UART bus used is the uart_mock component below
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+# Simulate a non-hardware UART (e.g., USB UART) by not setting rx_full_threshold.
+# This leaves it at the default sentinel value (0), triggering the 50ms fallback timeout.
+uart_mock:
+  - id: virtual_uart_dev
+    baud_rate: 9600
+    auto_start: false
+    debug:
+    on_tx:
+      - then:
+          - if:
+              condition: #Read 80 input registers on device 2, starting at address 0 (SDM meter request)
+                lambda: "return data == std::vector<uint8_t>({0x02,0x04,0x00,0x00,0x00,0x50,0xF0,0x05});"
+              then:
+                - uart_mock.inject_rx: # First USB packet: SDM meter response part 1
+                    !lambda return {0x02,0x04,0xA0,0x43,0x73,0x19,0x9A,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x3F,0x80,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
+                - uart_mock.inject_rx: # Second USB packet: rest of response (staged with 40ms latency)
+                    delay: 40ms
+                    data: !lambda return{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                      0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x42,0x6F,0xCC,0xCD,0x43,0x7C,0xB8,0x10,0x3D,0x38,0x51,0xEC,
+                      0x43,0x81,0x1B,0xE7,0x3B,0x03,0x12,0x6F,0x50,0x1B};
+
+modbus:
+  uart_id: virtual_uart_dev
+  turnaround_time: 10ms
+
+sensor:
+  - platform: sdm_meter
+    address: 2
+    update_interval: 1s
+    phase_a:
+      voltage:
+        name: sdm_voltage
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    id: start_scenario_btn
+    on_press:
+      - lambda: 'id(virtual_uart_dev).start_scenario();'

tests/integration/fixtures/uart_mock_modbus_timing.yaml

@@ -0,0 +1,64 @@
+esphome:
+  name: uart-mock-modbus-test
+
+host:
+api:
+logger:
+  level: VERBOSE
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+# Dummy uart entry to satisfy modbus's DEPENDENCIES = ["uart"]
+# The actual UART bus used is the uart_mock component below
+uart:
+  baud_rate: 115200
+  port: /dev/null
+
+uart_mock:
+  - id: virtual_uart_dev
+    baud_rate: 9600
+    rx_full_threshold: 120
+    rx_timeout: 2
+    auto_start: false
+    debug:
+    on_tx:
+      - then:
+          - if:
+              condition: #Read 80 input registers on device 2, starting at address 0 (SDM meter request)
+                lambda: "return data == std::vector<uint8_t>({0x02,0x04,0x00,0x00,0x00,0x50,0xF0,0x05});"
+              then:
+                - uart_mock.inject_rx: # Good response from SDM meter with CRC. Voltage is 243V
+                    !lambda return {0x02,0x04,0xA0,0x43,0x73,0x19,0x9A,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x3F,0x80,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
+                - delay: 120ms # Simulate some delay for UART buffer to fill before next part of response (1ms = 1 byte at 9600 baud)
+                - uart_mock.inject_rx: # Rest of response (including CRC)
+                    !lambda return{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+                    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x42,0x6F,0xCC,0xCD,0x43,0x7C,0xB8,0x10,0x3D,0x38,0x51,0xEC,
+                    0x43,0x81,0x1B,0xE7,0x3B,0x03,0x12,0x6F,0x50,0x1B};
+
+modbus:
+  uart_id: virtual_uart_dev
+  turnaround_time: 10ms
+
+sensor:
+  - platform: sdm_meter
+    address: 2
+    update_interval: 1s
+    phase_a:
+      voltage:
+        name: sdm_voltage
+
+button:
+  - platform: template
+    name: "Start Scenario"
+    id: start_scenario_btn
+    on_press:
+      - lambda: 'id(virtual_uart_dev).start_scenario();'

tests/integration/state_utils.py

@@ -3,10 +3,18 @@
 from __future__ import annotations
 
 import asyncio
+from collections.abc import Callable
 import logging
 from typing import TypeVar
 
-from aioesphomeapi import ButtonInfo, EntityInfo, EntityState
+from aioesphomeapi import (
+    BinarySensorState,
+    ButtonInfo,
+    EntityInfo,
+    EntityState,
+    SensorState,
+    TextSensorState,
+)
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -234,3 +242,107 @@ class InitialStateHelper:
             asyncio.TimeoutError: If initial states aren't received within timeout
         """
         await asyncio.wait_for(self._initial_states_received, timeout=timeout)
+
+
+class SensorStateCollector:
+    """Collects sensor, binary sensor, and text sensor state updates with wait helpers.
+
+    Usage:
+        collector = SensorStateCollector(
+            sensor_names=["moving_distance", "still_distance"],
+            binary_sensor_names=["has_target"],
+            text_sensor_names=["direction"],
+        )
+        # Use collector.on_state as the callback (or wrap it)
+        client.subscribe_states(helper.on_state_wrapper(collector.on_state))
+
+        # Wait for all sensors to have at least one value
+        await collector.wait_for_all(timeout=3.0)
+
+        # Access collected states
+        assert collector.sensor_states["moving_distance"][0] == approx(100.0)
+        assert collector.text_sensor_states["direction"][0] == "Approaching"
+    """
+
+    def __init__(
+        self,
+        sensor_names: list[str],
+        binary_sensor_names: list[str] | None = None,
+        text_sensor_names: list[str] | None = None,
+        entities: list[EntityInfo] | None = None,
+    ) -> None:
+        self.sensor_states: dict[str, list[float]] = {name: [] for name in sensor_names}
+        self.binary_states: dict[str, list[bool]] = {
+            name: [] for name in (binary_sensor_names or [])
+        }
+        self.text_sensor_states: dict[str, list[str]] = {
+            name: [] for name in (text_sensor_names or [])
+        }
+        self._key_to_sensor: dict[int, str] = {}
+        self._waiters: list[tuple[Callable[[], bool], asyncio.Future[bool]]] = []
+
+        if entities is not None:
+            self.build_key_mapping(entities)
+
+    def build_key_mapping(self, entities: list[EntityInfo]) -> None:
+        """Build key-to-name mapping from entities. Sorted by descending length."""
+        all_names = (
+            list(self.sensor_states.keys())
+            + list(self.binary_states.keys())
+            + list(self.text_sensor_states.keys())
+        )
+        all_names.sort(key=len, reverse=True)
+        self._key_to_sensor = build_key_to_entity_mapping(entities, all_names)
+
+    def on_state(self, state: EntityState) -> None:
+        """Process a state update."""
+        if isinstance(state, SensorState) and not state.missing_state:
+            sensor_name = self._key_to_sensor.get(state.key)
+            if sensor_name and sensor_name in self.sensor_states:
+                self.sensor_states[sensor_name].append(state.state)
+                self._check_waiters()
+        elif isinstance(state, BinarySensorState):
+            sensor_name = self._key_to_sensor.get(state.key)
+            if sensor_name and sensor_name in self.binary_states:
+                self.binary_states[sensor_name].append(state.state)
+                self._check_waiters()
+        elif isinstance(state, TextSensorState) and not state.missing_state:
+            sensor_name = self._key_to_sensor.get(state.key)
+            if sensor_name and sensor_name in self.text_sensor_states:
+                self.text_sensor_states[sensor_name].append(state.state)
+                self._check_waiters()
+
+    def _check_waiters(self) -> None:
+        """Check all pending waiters and resolve any whose condition is met."""
+        for condition, future in self._waiters:
+            if not future.done() and condition():
+                future.set_result(True)
+
+    def _all_have_values(self) -> bool:
+        """Check if all sensor, binary sensor, and text sensor lists have at least one value."""
+        return (
+            all(len(v) >= 1 for v in self.sensor_states.values())
+            and all(len(v) >= 1 for v in self.binary_states.values())
+            and all(len(v) >= 1 for v in self.text_sensor_states.values())
+        )
+
+    async def wait_for_all(self, timeout: float = 3.0) -> None:
+        """Wait until all sensors and binary sensors have at least one value."""
+        if self._all_have_values():
+            return
+        future: asyncio.Future[bool] = asyncio.get_running_loop().create_future()
+        self._waiters.append((self._all_have_values, future))
+        await asyncio.wait_for(future, timeout=timeout)
+
+    def add_waiter(self, condition: Callable[[], bool]) -> asyncio.Future[bool]:
+        """Add a custom waiter that resolves when condition returns True.
+
+        Returns:
+            A future that resolves when the condition is met.
+        """
+        future: asyncio.Future[bool] = asyncio.get_running_loop().create_future()
+        if condition():
+            future.set_result(True)
+        else:
+            self._waiters.append((condition, future))
+        return future

tests/integration/test_micros_to_millis.py

@@ -0,0 +1,46 @@
+"""Integration test for micros_to_millis Euclidean decomposition."""
+
+from __future__ import annotations
+
+import asyncio
+import re
+
+import pytest
+
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_micros_to_millis(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test that micros_to_millis matches reference uint64 division."""
+
+    all_passed = asyncio.Event()
+    failures: list[str] = []
+
+    def on_log_line(line: str) -> None:
+        clean_line = re.sub(r"\x1b\[[0-9;]*m", "", line)
+        if "ALL_PASSED" in clean_line:
+            all_passed.set()
+        elif "FAILED" in clean_line and "[MTM" in clean_line:
+            failures.append(clean_line)
+
+    async with (
+        run_compiled(yaml_config, line_callback=on_log_line),
+        api_client_connected() as client,
+    ):
+        device_info = await client.device_info()
+        assert device_info is not None
+        assert device_info.name == "micros-to-millis-test"
+
+        try:
+            await asyncio.wait_for(all_passed.wait(), timeout=2.0)
+        except TimeoutError:
+            if failures:
+                pytest.fail(f"micros_to_millis failures: {failures}")
+            pytest.fail("micros_to_millis test timed out")
+
+        assert not failures, f"micros_to_millis failures: {failures}"

tests/integration/test_oversized_payloads.py

@@ -17,10 +17,10 @@ async def test_oversized_payload_plaintext(
 ) -> None:
     """Test that oversized payloads (>32768 bytes) from client cause disconnection without crashing."""
     process_exited = False
-    helper_log_found = False
+    helper_log_event = asyncio.Event()
 
     def check_logs(line: str) -> None:
-        nonlocal process_exited, helper_log_found
+        nonlocal process_exited
         # Check for signs that the process exited/crashed
         if "Segmentation fault" in line or "core dumped" in line:
             process_exited = True
@@ -30,7 +30,7 @@ async def test_oversized_payload_plaintext(
             and "Bad packet: message size" in line
             and "exceeds maximum" in line
         ):
-            helper_log_found = True
+            helper_log_event.set()
 
     async with run_compiled(yaml_config, line_callback=check_logs):
         async with api_client_connected_with_disconnect() as (client, disconnect_event):
@@ -54,10 +54,13 @@ async def test_oversized_payload_plaintext(
 
         # After disconnection, verify process didn't crash
         assert not process_exited, "ESPHome process should not crash"
-        # Verify we saw the expected HELPER_LOG message
-        assert helper_log_found, (
-            "Expected to see HELPER_LOG about message size exceeding maximum"
-        )
+        # Wait for the expected log message (may arrive after disconnect event)
+        try:
+            await asyncio.wait_for(helper_log_event.wait(), timeout=2.0)
+        except TimeoutError:
+            pytest.fail(
+                "Expected to see HELPER_LOG about message size exceeding maximum"
+            )
 
         # Try to reconnect to verify the process is still running
         async with api_client_connected_with_disconnect() as (client2, _):
@@ -77,10 +80,10 @@ async def test_oversized_protobuf_message_id_plaintext(
     This tests the message type limit - message IDs must fit in a uint16_t (0-65535).
     """
     process_exited = False
-    helper_log_found = False
+    helper_log_event = asyncio.Event()
 
     def check_logs(line: str) -> None:
-        nonlocal process_exited, helper_log_found
+        nonlocal process_exited
         # Check for signs that the process exited/crashed
         if "Segmentation fault" in line or "core dumped" in line:
             process_exited = True
@@ -90,7 +93,7 @@ async def test_oversized_protobuf_message_id_plaintext(
             and "Bad packet: message type" in line
             and "exceeds maximum" in line
         ):
-            helper_log_found = True
+            helper_log_event.set()
 
     async with run_compiled(yaml_config, line_callback=check_logs):
         async with api_client_connected_with_disconnect() as (client, disconnect_event):
@@ -114,10 +117,13 @@ async def test_oversized_protobuf_message_id_plaintext(
 
         # After disconnection, verify process didn't crash
         assert not process_exited, "ESPHome process should not crash"
-        # Verify we saw the expected HELPER_LOG message
-        assert helper_log_found, (
-            "Expected to see HELPER_LOG about message type exceeding maximum"
-        )
+        # Wait for the expected log message (may arrive after disconnect event)
+        try:
+            await asyncio.wait_for(helper_log_event.wait(), timeout=2.0)
+        except TimeoutError:
+            pytest.fail(
+                "Expected to see HELPER_LOG about message type exceeding maximum"
+            )
 
         # Try to reconnect to verify the process is still running
         async with api_client_connected_with_disconnect() as (client2, _):
@@ -135,10 +141,10 @@ async def test_oversized_payload_noise(
     """Test that oversized payloads from client cause disconnection without crashing with noise encryption."""
     noise_key = "N4Yle5YirwZhPiHHsdZLdOA73ndj/84veVaLhTvxCuU="
     process_exited = False
-    helper_log_found = False
+    helper_log_event = asyncio.Event()
 
     def check_logs(line: str) -> None:
-        nonlocal process_exited, helper_log_found
+        nonlocal process_exited
         # Check for signs that the process exited/crashed
         if "Segmentation fault" in line or "core dumped" in line:
             process_exited = True
@@ -149,7 +155,7 @@ async def test_oversized_payload_noise(
             and "Bad packet: message size" in line
             and "exceeds maximum" in line
         ):
-            helper_log_found = True
+            helper_log_event.set()
 
     async with run_compiled(yaml_config, line_callback=check_logs):
         async with api_client_connected_with_disconnect(noise_psk=noise_key) as (
@@ -177,10 +183,13 @@ async def test_oversized_payload_noise(
 
         # After disconnection, verify process didn't crash
         assert not process_exited, "ESPHome process should not crash"
-        # Verify we saw the expected HELPER_LOG message
-        assert helper_log_found, (
-            "Expected to see HELPER_LOG about message size exceeding maximum"
-        )
+        # Wait for the expected log message (may arrive after disconnect event)
+        try:
+            await asyncio.wait_for(helper_log_event.wait(), timeout=2.0)
+        except TimeoutError:
+            pytest.fail(
+                "Expected to see HELPER_LOG about message size exceeding maximum"
+            )
 
         # Try to reconnect to verify the process is still running
         async with api_client_connected_with_disconnect(noise_psk=noise_key) as (
@@ -274,10 +283,10 @@ async def test_noise_corrupt_encrypted_frame(
     """
     noise_key = "N4Yle5YirwZhPiHHsdZLdOA73ndj/84veVaLhTvxCuU="
     process_exited = False
-    cipherstate_failed = False
+    cipherstate_event = asyncio.Event()
 
     def check_logs(line: str) -> None:
-        nonlocal process_exited, cipherstate_failed
+        nonlocal process_exited
         # Check for signs that the process exited/crashed
         if "Segmentation fault" in line or "core dumped" in line:
             process_exited = True
@@ -290,7 +299,7 @@ async def test_noise_corrupt_encrypted_frame(
             "[W][api.connection" in line
             and "Reading failed CIPHERSTATE_DECRYPT_FAILED" in line
         ):
-            cipherstate_failed = True
+            cipherstate_event.set()
 
     async with run_compiled(yaml_config, line_callback=check_logs):
         async with api_client_connected_with_disconnect(noise_psk=noise_key) as (
@@ -326,10 +335,14 @@ async def test_noise_corrupt_encrypted_frame(
         assert not process_exited, (
             "ESPHome process should not crash on corrupt encrypted frames"
         )
-        # Verify we saw the expected log message about decryption failure
-        assert cipherstate_failed, (
-            "Expected to see log about noise_cipherstate_decrypt failure or CIPHERSTATE_DECRYPT_FAILED"
-        )
+        # Wait for the expected log message (may arrive after disconnect event)
+        try:
+            await asyncio.wait_for(cipherstate_event.wait(), timeout=2.0)
+        except TimeoutError:
+            pytest.fail(
+                "Expected to see log about noise_cipherstate_decrypt failure"
+                " or CIPHERSTATE_DECRYPT_FAILED"
+            )
 
         # Verify we can still reconnect after handling the corrupt frame
         async with api_client_connected_with_disconnect(noise_psk=noise_key) as (

tests/integration/test_uart_mock_ld2410.py

@@ -0,0 +1,265 @@
+"""Integration test for LD2410 component with mock UART.
+
+Tests:
+test_uart_mock_ld2410 (normal mode):
+  1. Happy path - valid data frame publishes correct sensor values
+  2. Garbage resilience - random bytes don't crash the component
+  3. Truncated frame handling - partial frame doesn't corrupt state
+  4. Buffer overflow recovery - overflow resets the parser
+  5. Post-overflow parsing - next valid frame after overflow is parsed correctly
+  6. TX logging - verifies LD2410 sends expected setup commands
+
+test_uart_mock_ld2410_engineering (engineering mode):
+  1. Engineering mode frames with per-gate energy data and light sensor
+  2. Multi-byte still distance (291cm) using high byte > 0
+  3. Out pin presence binary sensor
+  4. Gate energy sensor values from real device captures
+"""
+
+from __future__ import annotations
+
+import asyncio
+from pathlib import Path
+
+from aioesphomeapi import ButtonInfo
+import pytest
+
+from .state_utils import InitialStateHelper, SensorStateCollector, find_entity
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_uart_mock_ld2410(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test LD2410 data parsing with happy path, garbage, overflow, and recovery."""
+    # Replace external component path placeholder
+    external_components_path = str(
+        Path(__file__).parent / "fixtures" / "external_components"
+    )
+    yaml_config = yaml_config.replace(
+        "EXTERNAL_COMPONENT_PATH", external_components_path
+    )
+
+    loop = asyncio.get_running_loop()
+
+    # Track overflow warning in logs
+    overflow_seen = loop.create_future()
+
+    # Track TX data logged by the mock for assertions
+    tx_log_lines: list[str] = []
+
+    def line_callback(line: str) -> None:
+        if "Max command length exceeded" in line and not overflow_seen.done():
+            overflow_seen.set_result(True)
+        # Capture all TX log lines from uart_mock
+        if "uart_mock" in line and "TX " in line:
+            tx_log_lines.append(line)
+
+    collector = SensorStateCollector(
+        sensor_names=[
+            "moving_distance",
+            "still_distance",
+            "moving_energy",
+            "still_energy",
+            "detection_distance",
+        ],
+        binary_sensor_names=[
+            "has_target",
+            "has_moving_target",
+            "has_still_target",
+        ],
+    )
+
+    # Signal when we see recovery frame values
+    recovery_received = collector.add_waiter(
+        lambda: pytest.approx(50.0) in collector.sensor_states["moving_distance"]
+    )
+
+    async with (
+        run_compiled(yaml_config, line_callback=line_callback),
+        api_client_connected() as client,
+    ):
+        entities, _ = await client.list_entities_services()
+        collector.build_key_mapping(entities)
+
+        # Set up initial state helper
+        initial_state_helper = InitialStateHelper(entities)
+        client.subscribe_states(
+            initial_state_helper.on_state_wrapper(collector.on_state)
+        )
+
+        try:
+            await initial_state_helper.wait_for_initial_states()
+        except TimeoutError:
+            pytest.fail("Timeout waiting for initial states")
+
+        # Start the UART mock scenario now that we're subscribed
+        start_btn = find_entity(entities, "start_scenario", ButtonInfo)
+        assert start_btn is not None, "Start Scenario button not found"
+        client.button_command(start_btn.key)
+
+        # Wait for Phase 1 - all sensors and binary sensors have at least one value
+        try:
+            await collector.wait_for_all(timeout=3.0)
+        except TimeoutError:
+            pytest.fail(
+                f"Timeout waiting for Phase 1 frame. Received:\n"
+                f"  sensor_states: {collector.sensor_states}\n"
+                f"  binary_states: {collector.binary_states}"
+            )
+
+        # Phase 1 values: moving=100, still=120, energy=50/25, detect=300
+        assert collector.sensor_states["moving_distance"][0] == pytest.approx(100.0)
+        assert collector.sensor_states["still_distance"][0] == pytest.approx(120.0)
+        assert collector.sensor_states["moving_energy"][0] == pytest.approx(50.0)
+        assert collector.sensor_states["still_energy"][0] == pytest.approx(25.0)
+        assert collector.sensor_states["detection_distance"][0] == pytest.approx(300.0)
+
+        # Wait for the recovery frame (Phase 5) to be parsed
+        # This proves the component survived garbage + truncated + overflow
+        try:
+            await asyncio.wait_for(recovery_received, timeout=15.0)
+        except TimeoutError:
+            pytest.fail(
+                f"Timeout waiting for recovery frame. Received:\n"
+                f"  sensor_states: {collector.sensor_states}"
+            )
+
+        # Verify overflow warning was logged
+        assert overflow_seen.done(), (
+            "Expected 'Max command length exceeded' warning in logs"
+        )
+
+        # Verify LD2410 sent setup commands (TX logging)
+        # LD2410 sends 7 commands during setup: FF (config on), A0 (version),
+        # A5 (MAC), AB (distance res), AE (light), 61 (params), FE (config off)
+        assert len(tx_log_lines) > 0, "Expected TX log lines from uart_mock"
+        tx_data = " ".join(tx_log_lines)
+        assert "FD:FC:FB:FA" in tx_data, (
+            "Expected LD2410 command frame header FD:FC:FB:FA in TX log"
+        )
+        assert "04:03:02:01" in tx_data, (
+            "Expected LD2410 command frame footer 04:03:02:01 in TX log"
+        )
+
+        # Recovery frame: moving=50, still=75, energy=100/80, detect=127
+        recovery_idx = next(
+            i
+            for i, v in enumerate(collector.sensor_states["moving_distance"])
+            if v == pytest.approx(50.0)
+        )
+        assert collector.sensor_states["still_distance"][recovery_idx] == pytest.approx(
+            75.0
+        )
+        assert collector.sensor_states["moving_energy"][recovery_idx] == pytest.approx(
+            100.0
+        )
+        assert collector.sensor_states["still_energy"][recovery_idx] == pytest.approx(
+            80.0
+        )
+        assert collector.sensor_states["detection_distance"][
+            recovery_idx
+        ] == pytest.approx(127.0)
+
+        # Verify binary sensors detected targets (from Phase 1 frame)
+        assert collector.binary_states["has_target"][0] is True
+        assert collector.binary_states["has_moving_target"][0] is True
+        assert collector.binary_states["has_still_target"][0] is True
+
+
+@pytest.mark.asyncio
+async def test_uart_mock_ld2410_engineering(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test LD2410 engineering mode with per-gate energy, light, and multi-byte distance."""
+    external_components_path = str(
+        Path(__file__).parent / "fixtures" / "external_components"
+    )
+    yaml_config = yaml_config.replace(
+        "EXTERNAL_COMPONENT_PATH", external_components_path
+    )
+
+    collector = SensorStateCollector(
+        sensor_names=[
+            "moving_distance",
+            "still_distance",
+            "moving_energy",
+            "still_energy",
+            "detection_distance",
+            "light",
+            "gate_0_move_energy",
+            "gate_1_move_energy",
+            "gate_2_move_energy",
+            "gate_0_still_energy",
+            "gate_1_still_energy",
+            "gate_2_still_energy",
+        ],
+        binary_sensor_names=[
+            "has_target",
+            "has_moving_target",
+            "has_still_target",
+            "out_pin_presence",
+        ],
+    )
+
+    # Signal when we see Phase 3 frame values
+    phase3_received = collector.add_waiter(
+        lambda: pytest.approx(291.0) in collector.sensor_states["still_distance"]
+    )
+
+    async with (
+        run_compiled(yaml_config),
+        api_client_connected() as client,
+    ):
+        entities, _ = await client.list_entities_services()
+        collector.build_key_mapping(entities)
+
+        initial_state_helper = InitialStateHelper(entities)
+        client.subscribe_states(
+            initial_state_helper.on_state_wrapper(collector.on_state)
+        )
+
+        try:
+            await initial_state_helper.wait_for_initial_states()
+        except TimeoutError:
+            pytest.fail("Timeout waiting for initial states")
+
+        # Start the UART mock scenario now that we're subscribed
+        start_btn = find_entity(entities, "start_scenario", ButtonInfo)
+        assert start_btn is not None, "Start Scenario button not found"
+        client.button_command(start_btn.key)
+
+        # Wait for Phase 1 - all sensors and binary sensors have at least one value
+        try:
+            await collector.wait_for_all(timeout=3.0)
+        except TimeoutError:
+            pytest.fail(
+                f"Timeout waiting for Phase 1 frame. Received:\n"
+                f"  sensor_states: {collector.sensor_states}\n"
+                f"  binary_states: {collector.binary_states}"
+            )
+
+        # Phase 1 values (engineering mode frame):
+        # moving=30, energy=100, still=30, energy=100, detect=0
+        assert collector.sensor_states["moving_distance"][0] == pytest.approx(30.0)
+        assert collector.sensor_states["still_distance"][0] == pytest.approx(30.0)
+        assert collector.sensor_states["gate_0_move_energy"][0] == pytest.approx(100.0)
+        assert collector.sensor_states["gate_1_move_energy"][0] == pytest.approx(65.0)
+        assert collector.sensor_states["light"][0] == pytest.approx(87.0)
+        assert collector.binary_states["out_pin_presence"][0] is True
+
+        # Wait for Phase 3 frame (still_distance = 291cm, multi-byte)
+        try:
+            await asyncio.wait_for(phase3_received, timeout=15.0)
+        except TimeoutError:
+            pytest.fail(
+                f"Timeout waiting for Phase 3 frame. Received:\n"
+                f"  still_distance: {collector.sensor_states['still_distance']}"
+            )
+
+        assert pytest.approx(291.0) in collector.sensor_states["still_distance"]