[core] Assert a frame came back before each resync() in the FrameReader tests

AGENTS.md

@@ -216,9 +216,10 @@ file does, and it is the authority when they disagree. The most useful starting
         the helper's arguments instead of writing a loop. 7-byte BCD RTC calendars use `time::decode_bcd_calendar<LAYOUT>`
         and `encode_bcd_calendar<LAYOUT>` with `EPSON_BCD_CALENDAR`, `DS_BCD_CALENDAR` or `PCF_BCD_CALENDAR`.
     *   **Bus helpers:** UART drains with `read_available(on_byte)` and `discard_available()`, text lines with
-        `LineReader<N>`; I2C has `update_register`, `write_registers` (PROGMEM `I2CRegValue` table), `check_chip_id`
-        and `read_bytes_16_le`. `if (!this->status_comm_result(ok)) return;` sets or clears the warning.
-        A child sensor that skips repeated values is `SUB_SENSOR_WITH_DEDUP(name, type)`.
+        `LineReader<N>`, fixed-length binary frames with `FrameReader<N, HEADER...>`; I2C has `update_register`,
+        `write_registers` (PROGMEM `I2CRegValue` table), `check_chip_id` and `read_bytes_16_le`.
+        `if (!this->status_comm_result(ok)) return;` sets or clears the warning. A child sensor that skips repeated
+        values is `SUB_SENSOR_WITH_DEDUP(name, type)`.
     *   **An unset float is `NAN`**, not `optional<float>`; the optional costs 4 to 8 bytes of padding per member.
     *   **`PollingComponent` first runs `update()`** after a random share of the interval; call `this->update()` at the
         end of `setup()` when the entities need a state at boot.

esphome/components/ds248x/ds248x_one_wire_bus.cpp

@@ -1,6 +1,5 @@
 #include "ds248x_one_wire_bus.h"
 #include "ds248x.h"
-#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 namespace esphome::ds248x {
@@ -152,7 +151,11 @@ uint64_t DS248xOneWireBus::search_int() {
     }
 
     // Update address based on direction taken
-    assign_bits(address, bit_mask, dir_taken);
+    if (dir_taken) {
+      address |= bit_mask;
+    } else {
+      address &= ~bit_mask;
+    }
   }
 
   // Search successful

esphome/components/htu21d/htu21d.cpp

@@ -1,7 +1,6 @@
 #include "htu21d.h"
-#include "esphome/core/hal.h"
-#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
+#include "esphome/core/hal.h"
 
 namespace esphome::htu21d {
 
@@ -113,7 +112,11 @@ void HTU21DComponent::set_heater(bool status) {
     this->status_set_warning();
     return;
   }
-  assign_bits(raw_heater, 1 << HTU21D_REG_HTRE_BIT, status);
+  if (status) {
+    raw_heater |= (1 << HTU21D_REG_HTRE_BIT);
+  } else {
+    raw_heater &= ~(1 << HTU21D_REG_HTRE_BIT);
+  }
   if (this->write_register(HTU21D_WRITERHT_REG_CMD, &raw_heater, 1) != i2c::ERROR_OK) {
     this->status_set_warning();
     return;

esphome/components/light/light_call.h

@@ -1,7 +1,6 @@
 #pragma once
 
 #include "light_color_values.h"
-#include "esphome/core/helpers.h"
 #include "esphome/core/string_ref.h"
 
 namespace esphome {
@@ -230,7 +229,13 @@ class LightCall {
   inline bool get_save_() { return (this->flags_ & FLAG_SAVE) != 0; }
 
   // Helper to set flag - defaults to true for common case
-  void set_flag_(FieldFlags flag, bool value = true) ESPHOME_ALWAYS_INLINE { assign_bits(this->flags_, flag, value); }
+  void set_flag_(FieldFlags flag, bool value = true) ESPHOME_ALWAYS_INLINE {
+    if (value) {
+      this->flags_ |= flag;
+    } else {
+      this->flags_ &= ~flag;
+    }
+  }
 
   // Helper to clear flag - reduces code size for common case
   void clear_flag_(FieldFlags flag) ESPHOME_ALWAYS_INLINE { this->flags_ &= ~flag; }

esphome/components/media_player/media_player.cpp

@@ -1,7 +1,6 @@
 #include "media_player.h"
-#include "esphome/core/controller_registry.h"
 #include "esphome/core/defines.h"
-#include "esphome/core/helpers.h"
+#include "esphome/core/controller_registry.h"
 #include "esphome/core/log.h"
 #include "esphome/core/progmem.h"
 
@@ -78,12 +77,19 @@ const char *media_player_command_to_string(MediaPlayerCommand command) {
 }
 
 void MediaPlayerTraits::set_supports_pause(bool supports_pause) {
-  assign_bits(this->feature_flags_, MediaPlayerEntityFeature::PAUSE | MediaPlayerEntityFeature::PLAY, supports_pause);
+  if (supports_pause) {
+    this->feature_flags_ |= MediaPlayerEntityFeature::PAUSE | MediaPlayerEntityFeature::PLAY;
+  } else {
+    this->feature_flags_ &= ~(MediaPlayerEntityFeature::PAUSE | MediaPlayerEntityFeature::PLAY);
+  }
 }
 
 void MediaPlayerTraits::set_supports_turn_off_on(bool supports_turn_off_on) {
-  assign_bits(this->feature_flags_, MediaPlayerEntityFeature::TURN_OFF | MediaPlayerEntityFeature::TURN_ON,
-              supports_turn_off_on);
+  if (supports_turn_off_on) {
+    this->feature_flags_ |= MediaPlayerEntityFeature::TURN_OFF | MediaPlayerEntityFeature::TURN_ON;
+  } else {
+    this->feature_flags_ &= ~(MediaPlayerEntityFeature::TURN_OFF | MediaPlayerEntityFeature::TURN_ON);
+  }
 }
 
 void MediaPlayerCall::validate_() {

esphome/components/mpr121/mpr121.cpp

@@ -3,7 +3,6 @@
 #include <cstdint>
 
 #include "esphome/core/hal.h"
-#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 namespace esphome::mpr121 {
@@ -85,7 +84,11 @@ bool MPR121Component::digital_read(uint8_t pin) { return (this->gpio_input_ & (1
 
 void MPR121Component::digital_write(uint8_t pin, bool value) {
   const uint8_t ionum = pin - 4;
-  assign_bits(this->gpio_output_, 1 << ionum, value);
+  if (value) {
+    this->gpio_output_ |= (1 << ionum);
+  } else {
+    this->gpio_output_ &= ~(1 << ionum);
+  }
   this->flush_gpio_();
 }
 

esphome/components/provisioning/provisioning.h

@@ -46,7 +46,11 @@ class ProvisioningManager : public Component {
   void set_source_provisioned(uint8_t source, bool provisioned) {
     if (source >= MAX_SOURCES)
       return;
-    assign_bits(this->provisioned_mask_, 1UL << source, provisioned);
+    if (provisioned) {
+      this->provisioned_mask_ |= (1UL << source);
+    } else {
+      this->provisioned_mask_ &= ~(1UL << source);
+    }
   }
 
   // True once every registered source is provisioned. Config validation guarantees

esphome/components/socket/bsd_sockets_impl.cpp

@@ -62,7 +62,11 @@ int BSDSocketImpl::setblocking(bool blocking) {
   if (fl < 0) {
     return fl;
   }
-  assign_bits(fl, O_NONBLOCK, !blocking);
+  if (blocking) {
+    fl &= ~O_NONBLOCK;
+  } else {
+    fl |= O_NONBLOCK;
+  }
   return ::fcntl(this->fd_, F_SETFL, fl);
 }
 

esphome/components/socket/lwip_sockets_impl.cpp

@@ -52,7 +52,11 @@ int LwIPSocketImpl::setblocking(bool blocking) {
   if (fl < 0) {
     return fl;
   }
-  assign_bits(fl, O_NONBLOCK, !blocking);
+  if (blocking) {
+    fl &= ~O_NONBLOCK;
+  } else {
+    fl |= O_NONBLOCK;
+  }
   return lwip_fcntl(this->fd_, F_SETFL, fl);
 }
 

esphome/components/uart/uart_component_host.cpp

@@ -162,7 +162,11 @@ void HostUartComponent::setup() {
       break;
   };
   // Set stop bits
-  assign_bits(options.c_cflag, CSTOPB, this->stop_bits_ == 2);
+  if (this->stop_bits_ == 2) {
+    options.c_cflag |= CSTOPB;
+  } else {
+    options.c_cflag &= ~CSTOPB;
+  }
   cfsetispeed(&options, baud);
   cfsetospeed(&options, baud);
   tcsetattr(this->file_descriptor_, TCSANOW, &options);

esphome/components/ufire_ec/ufire_ec.cpp

@@ -1,4 +1,3 @@
-#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "ufire_ec.h"
 #include <cmath>
@@ -20,8 +19,11 @@ void UFireECComponent::setup() {
   // Write option for temperature adjustments
   uint8_t config;
   this->read_byte(REGISTER_CONFIG, &config);
-  assign_bits(config, CONFIG_TEMP_COMPENSATION,
-              this->temperature_sensor_ != nullptr || this->temperature_sensor_external_ != nullptr);
+  if (this->temperature_sensor_ == nullptr && this->temperature_sensor_external_ == nullptr) {
+    config &= ~CONFIG_TEMP_COMPENSATION;
+  } else {
+    config |= CONFIG_TEMP_COMPENSATION;
+  }
   this->write_byte(REGISTER_CONFIG, config);
 
   // Update temperature compensation

esphome/components/ufire_ise/ufire_ise.cpp

@@ -1,4 +1,3 @@
-#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "ufire_ise.h"
 
@@ -21,8 +20,11 @@ void UFireISEComponent::setup() {
   // Write option for temperature adjustments
   uint8_t config;
   this->read_byte(REGISTER_CONFIG, &config);
-  assign_bits(config, CONFIG_TEMP_COMPENSATION,
-              this->temperature_sensor_ != nullptr || this->temperature_sensor_external_ != nullptr);
+  if (this->temperature_sensor_ == nullptr && this->temperature_sensor_external_ == nullptr) {
+    config &= ~CONFIG_TEMP_COMPENSATION;
+  } else {
+    config |= CONFIG_TEMP_COMPENSATION;
+  }
   this->write_byte(REGISTER_CONFIG, config);
 }
 

esphome/components/water_heater/water_heater.cpp

@@ -5,7 +5,6 @@
 #include "esphome/core/application.h"
 #include "esphome/core/controller_registry.h"
 #include "esphome/core/progmem.h"
-#include "esphome/core/helpers.h"
 
 #include <cmath>
 #include <cstring>
@@ -60,13 +59,21 @@ WaterHeaterCall &WaterHeaterCall::set_target_temperature_high(float temperature)
 }
 
 WaterHeaterCall &WaterHeaterCall::set_away(bool away) {
-  assign_bits(this->state_, WATER_HEATER_STATE_AWAY, away);
+  if (away) {
+    this->state_ |= WATER_HEATER_STATE_AWAY;
+  } else {
+    this->state_ &= ~WATER_HEATER_STATE_AWAY;
+  }
   this->state_mask_ |= WATER_HEATER_STATE_AWAY;
   return *this;
 }
 
 WaterHeaterCall &WaterHeaterCall::set_on(bool on) {
-  assign_bits(this->state_, WATER_HEATER_STATE_ON, on);
+  if (on) {
+    this->state_ |= WATER_HEATER_STATE_ON;
+  } else {
+    this->state_ &= ~WATER_HEATER_STATE_ON;
+  }
   this->state_mask_ |= WATER_HEATER_STATE_ON;
   return *this;
 }

esphome/components/water_heater/water_heater.h

@@ -252,7 +252,13 @@ class WaterHeater : public EntityBase {
   /// Set the state flags. Should only be called from control().
   void set_state_(uint32_t state) { this->state_ = state; }
   /// Set or clear a state flag. Should only be called from control().
-  void set_state_flag_(uint32_t flag, bool value) { assign_bits(this->state_, flag, value); }
+  void set_state_flag_(uint32_t flag, bool value) {
+    if (value) {
+      this->state_ |= flag;
+    } else {
+      this->state_ &= ~flag;
+    }
+  }
 
   WaterHeaterMode mode_{WATER_HEATER_MODE_OFF};
   float current_temperature_{NAN};

esphome/core/frame_reader.h

@@ -0,0 +1,67 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <type_traits>
+
+namespace esphome {
+
+/// Collects fixed length binary frames of N bytes that start with the header bytes HEADER...; the binary twin of
+/// LineReader. Bytes before a header are skipped; checksums are left to the caller.
+template<size_t N, uint8_t... HEADER> class FrameReader {
+  using pos_t = std::conditional_t<(N <= 0xFF), uint8_t, uint16_t>;
+  static constexpr size_t HEADER_LEN = sizeof...(HEADER);
+  static_assert(HEADER_LEN >= 1 && HEADER_LEN <= 8, "FrameReader takes 1 to 8 header bytes");  // bounds replay_() depth
+  static_assert(HEADER_LEN < N && N <= 0xFFFF, "FrameReader size out of range");
+
+ public:
+  /// Feed one byte; returns the completed frame, header included, valid until the next call, or nullptr.
+  const uint8_t *feed(uint8_t c) {
+    pos_t pos = this->pos_;
+    if (pos < HEADER_LEN && c != header_byte(pos)) {
+      // A later byte of the broken header, or c, may start the real one
+      this->buf_[pos] = c;
+      this->replay_(pos);
+      return nullptr;
+    }
+    this->buf_[pos++] = c;
+    if (pos < N) {
+      this->pos_ = pos;
+      return nullptr;
+    }
+    this->pos_ = 0;
+    return this->buf_;
+  }
+
+  /// Number of bytes of the partial frame; 0 after a frame is returned and while looking for a header.
+  size_t length() const { return this->pos_; }
+
+  /// Forget the partial frame and look for a header from the next byte.
+  void reset() { this->pos_ = 0; }
+
+  /// For a frame the caller rejected (bad checksum): drop its first byte and realign on a header in the rest.
+  /// Call only right after feed() returned that frame; use reset() otherwise.
+  void resync() { this->replay_(N - 1); }
+
+ protected:
+  // A fold, not an array, so no header table lands in RAM on ESP8266
+  static constexpr uint8_t header_byte(size_t i) {
+    size_t j = 0;
+    uint8_t r = 0;
+    ((r = (j++ == i) ? HEADER : r), ...);
+    return r;
+  }
+
+  // Start over and feed buf_[1..last] again; never completes a frame as last < N
+  void replay_(size_t last) {
+    this->pos_ = 0;
+    for (size_t i = 1; i <= last; i++) {
+      this->feed(this->buf_[i]);
+    }
+  }
+
+  uint8_t buf_[N];
+  pos_t pos_{0};
+};
+
+}  // namespace esphome

tests/components/core/frame_reader_test.cpp

@@ -0,0 +1,143 @@
+#include <gtest/gtest.h>
+#include <vector>
+#include "esphome/core/frame_reader.h"
+
+namespace esphome::core::testing {
+
+using Bytes = std::vector<uint8_t>;
+using Frames = std::vector<Bytes>;
+
+// Feeds bytes and collects every completed frame.
+template<size_t N, uint8_t... H> static Frames feed_all(FrameReader<N, H...> &reader, const Bytes &input) {
+  Frames frames;
+  for (uint8_t c : input) {
+    const uint8_t *frame = reader.feed(c);
+    if (frame != nullptr) {
+      EXPECT_EQ(reader.length(), 0u);
+      frames.emplace_back(frame, frame + N);
+    }
+  }
+  return frames;
+}
+
+static_assert(sizeof(FrameReader<4, 0xFF>) == 5);
+static_assert(sizeof(FrameReader<9, 0x55, 0x01, 0x01, 0x04>) == 10);
+static_assert(sizeof(FrameReader<0xFF, 0xAA>) == 0x100);
+static_assert(sizeof(FrameReader<0x100, 0xAA>) == 0x102);
+
+TEST(FrameReaderTest, SingleByteHeader) {
+  FrameReader<4, 0xFF> reader;
+  EXPECT_EQ(feed_all(reader, {0xFF, 0x01, 0x02, 0x02, 0xFF, 0x03, 0x04, 0x06}),
+            (Frames{{0xFF, 0x01, 0x02, 0x02}, {0xFF, 0x03, 0x04, 0x06}}));
+}
+
+TEST(FrameReaderTest, SkipsBytesBeforeHeader) {
+  FrameReader<3, 0xFF> reader;
+  EXPECT_EQ(feed_all(reader, {0x01, 0x02, 0xFF, 0x10, 0x20}), (Frames{{0xFF, 0x10, 0x20}}));
+}
+
+TEST(FrameReaderTest, HeaderByteInsidePayloadIsData) {
+  FrameReader<4, 0xFF> reader;
+  EXPECT_EQ(feed_all(reader, {0xFF, 0xFF, 0xFF, 0x00}), (Frames{{0xFF, 0xFF, 0xFF, 0x00}}));
+}
+
+TEST(FrameReaderTest, LengthTracksPartialFrame) {
+  FrameReader<4, 0xAA, 0xBB> reader;
+  EXPECT_EQ(reader.length(), 0u);
+  reader.feed(0x00);
+  EXPECT_EQ(reader.length(), 0u);
+  reader.feed(0xAA);
+  EXPECT_EQ(reader.length(), 1u);
+  reader.feed(0xBB);
+  reader.feed(0x01);
+  EXPECT_EQ(reader.length(), 3u);
+  reader.reset();
+  EXPECT_EQ(reader.length(), 0u);
+  EXPECT_EQ(feed_all(reader, {0x02, 0xAA, 0xBB, 0x03, 0x04}), (Frames{{0xAA, 0xBB, 0x03, 0x04}}));
+}
+
+TEST(FrameReaderTest, MultiByteHeaderMismatchRestarts) {
+  FrameReader<6, 0x55, 0x01, 0x01, 0x04> reader;
+  EXPECT_EQ(feed_all(reader, {0x55, 0x01, 0x02, 0x55, 0x01, 0x01, 0x04, 0x11, 0x22}),
+            (Frames{{0x55, 0x01, 0x01, 0x04, 0x11, 0x22}}));
+}
+
+TEST(FrameReaderTest, MismatchedByteCanStartHeader) {
+  FrameReader<6, 0x55, 0x01, 0x01, 0x04> reader;
+  // The second 0x55 breaks the first header and starts the real one
+  EXPECT_EQ(feed_all(reader, {0x55, 0x01, 0x55, 0x01, 0x01, 0x04, 0x11, 0x22}),
+            (Frames{{0x55, 0x01, 0x01, 0x04, 0x11, 0x22}}));
+}
+
+TEST(FrameReaderTest, RepeatedHeaderPrefixIsKept) {
+  // AA AA AA BB: the mismatch at the third byte still leaves AA AA matched
+  FrameReader<4, 0xAA, 0xAA, 0xBB> reader;
+  EXPECT_EQ(feed_all(reader, {0xAA, 0xAA, 0xAA, 0xBB, 0x01}), (Frames{{0xAA, 0xAA, 0xBB, 0x01}}));
+}
+
+TEST(FrameReaderTest, OverlappingHeaderPrefix) {
+  // A1 B2 A1 B2: the mismatch on the last B2 keeps the trailing A1 B2 as the start of the header
+  FrameReader<5, 0xA1, 0xB2, 0xA1, 0xC3> reader;
+  EXPECT_EQ(feed_all(reader, {0xA1, 0xB2, 0xA1, 0xB2, 0xA1, 0xC3, 0x07}), (Frames{{0xA1, 0xB2, 0xA1, 0xC3, 0x07}}));
+}
+
+TEST(FrameReaderTest, ResyncFindsHeaderInRejectedFrame) {
+  FrameReader<4, 0xFF> reader;
+  // Started mid-frame: the 0xFF taken as a header was payload; the real frame starts at the second 0xFF
+  const uint8_t *frame = nullptr;
+  for (uint8_t c : {0xFF, 0x12, 0xFF, 0x01}) {
+    frame = reader.feed(c);
+  }
+  ASSERT_NE(frame, nullptr);
+  reader.resync();
+  EXPECT_EQ(reader.length(), 2u);
+  EXPECT_EQ(feed_all(reader, {0x02, 0x02}), (Frames{{0xFF, 0x01, 0x02, 0x02}}));
+}
+
+TEST(FrameReaderTest, ResyncWithoutHeaderStartsOver) {
+  FrameReader<4, 0xFF> reader;
+  const uint8_t *frame = nullptr;
+  for (uint8_t c : {0xFF, 0x01, 0x02, 0x03}) {
+    frame = reader.feed(c);
+  }
+  ASSERT_NE(frame, nullptr);
+  reader.resync();
+  EXPECT_EQ(reader.length(), 0u);
+}
+
+TEST(FrameReaderTest, ResyncKeepsPartialHeaderAtEnd) {
+  FrameReader<5, 0x3C, 0x32> reader;
+  const uint8_t *frame = nullptr;
+  for (uint8_t c : {0x3C, 0x32, 0x00, 0x00, 0x3C}) {
+    frame = reader.feed(c);
+  }
+  ASSERT_NE(frame, nullptr);
+  reader.resync();
+  EXPECT_EQ(reader.length(), 1u);
+  EXPECT_EQ(feed_all(reader, {0x32, 0x01, 0x02, 0x03}), (Frames{{0x3C, 0x32, 0x01, 0x02, 0x03}}));
+}
+
+TEST(FrameReaderTest, ResyncMultiByteHeader) {
+  FrameReader<6, 0x3C, 0x32> reader;
+  const uint8_t *frame = nullptr;
+  for (uint8_t c : {0x3C, 0x32, 0x3C, 0x3C, 0x32, 0x09}) {
+    frame = reader.feed(c);
+  }
+  ASSERT_NE(frame, nullptr);
+  reader.resync();
+  EXPECT_EQ(reader.length(), 3u);
+  EXPECT_EQ(feed_all(reader, {0x0A, 0x0B, 0x0C}), (Frames{{0x3C, 0x32, 0x09, 0x0A, 0x0B, 0x0C}}));
+}
+
+TEST(FrameReaderTest, SixteenBitIndex) {
+  FrameReader<300, 0xAA, 0x55> reader;
+  Bytes input{0x00, 0xAA, 0x55};
+  input.resize(input.size() + 298, 0x42);
+  Frames frames = feed_all(reader, input);
+  ASSERT_EQ(frames.size(), 1u);
+  EXPECT_EQ(frames[0][0], 0xAA);
+  EXPECT_EQ(frames[0][1], 0x55);
+  EXPECT_EQ(frames[0][299], 0x42);
+}
+
+}  // namespace esphome::core::testing

tests/integration/README.md

@@ -58,30 +58,8 @@ The `InitialStateHelper` class solves a common problem in integration tests: whe
 - Provides debug logging to track state reception (use `--log-cli-level=DEBUG`)
 - Safe for concurrent use with multiple entity types
 
-#### Subscribing after the initial states (`state_utils.py`)
-
-`subscribe_after_initial_states()` does the `InitialStateHelper` setup in one call: it subscribes, waits
-for every entity's connect time state, and fails the test with the entities still missing on timeout.
-It returns a `StateSubscription` with `initial_states` (by key) and a `waiter`, a `StateWaiter` that sees
-every later state. `waiter.next_state(key=..., state_type=...)` arms a wait for the next matching state;
-call it before sending the command. `press_and_wait()` presses a button and returns the next state of a
-type, from one entity when `key=` is given:
-
-```python
-from .state_utils import press_and_wait, subscribe_after_initial_states
-
-entities, _ = await client.list_entities_services()
-sub = await subscribe_after_initial_states(client, entities)
-
-state = await press_and_wait(client, entities, sub.waiter, "set_position", CoverState)
-assert state.position == pytest.approx(0.5, abs=0.01)
-
-next_light = sub.waiter.next_state(key=light.key, state_type=LightState)
-client.light_command(key=light.key, state=True)
-assert (await next_light).state is True
-```
-
-Pass `on_state=` as well when the test also needs to collect every state.
+**Future work:**
+Consider converting existing integration tests to use `InitialStateHelper` for more reliable state tracking and to eliminate race conditions related to initial state broadcasts.
 
 #### Entity Lookup Helpers (`state_utils.py`)
 
@@ -225,24 +203,46 @@ async def test_my_sensor(
 
 ##### State Subscription Pattern
 
-**Recommended: Using subscribe_after_initial_states**
+**Recommended: Using InitialStateHelper**
 
-When an API client connects, ESPHome automatically sends the current state of all entities.
-`subscribe_after_initial_states()` (from `state_utils.py`) swallows these initial states and only forwards
-subsequent state changes, to your callback and to the returned `waiter`:
+When an API client connects, ESPHome automatically sends the current state of all entities. The `InitialStateHelper` (from `state_utils.py`) handles this by swallowing these initial states and only forwarding subsequent state changes to your test callback:
 
 ```python
-from .state_utils import subscribe_after_initial_states
+from .state_utils import InitialStateHelper
 
+# Track state changes with futures
+loop = asyncio.get_running_loop()
+states: dict[int, EntityState] = {}
+state_future: asyncio.Future[EntityState] = loop.create_future()
+
+
+def on_state(state: EntityState) -> None:
+    """This callback only receives NEW state changes, not initial states."""
+    states[state.key] = state
+    # Check for specific condition using isinstance
+    if isinstance(state, SensorState) and state.state == expected_value:
+        if not state_future.done():
+            state_future.set_result(state)
+
+
+# Get entities and set up state synchronization
 entities, services = await client.list_entities_services()
-sub = await subscribe_after_initial_states(client, entities)
+initial_state_helper = InitialStateHelper(entities)
 
-# Arm the wait before the action that produces the state
-expected = sub.waiter.expect(
-    lambda s: isinstance(s, SensorState) and s.state == expected_value
-)
+# Subscribe with the wrapper that filters initial states
+client.subscribe_states(initial_state_helper.on_state_wrapper(on_state))
+
+# Wait for all initial states to be broadcast; on timeout this fails the test
+# and lists the entities that never sent one
+await initial_state_helper.wait_for_initial_states()
+
+# Now perform your test actions - on_state will only receive new changes
 # ... trigger state changes ...
-result = await expected
+
+# Wait for expected state; on timeout the test fails and shows the states received
+result = await wait_or_fail(
+    state_future, 5.0, "Expected state not received", states=states
+)
 ```
 
 **Legacy: Manual State Tracking**
@@ -386,33 +386,37 @@ async with run_compiled(yaml_config, line_callback=on_log_line):
     # Test implementation
 ```
 
-To wait for log lines, use `LineWaiter` (`log_utils.py`) instead of a hand written
-callback with one future per pattern:
+Example using futures for specific log patterns:
 ```python
 import re
 
-from .log_utils import LineWaiter
+loop = asyncio.get_running_loop()
+connected_future = loop.create_future()
+service_future = loop.create_future()
 
-log = LineWaiter()
-# Arm expectations before the action that logs them; any number may be pending.
-connected = log.expect(re.compile(r"Client .* connected from"))
-value = log.expect(re.compile(r"value=(\d+)"))
+# Patterns to match
+connected_pattern = re.compile(r"Client .* connected from")
+service_pattern = re.compile(r"Service called")
 
-async with run_compiled(yaml_config, line_callback=log.callback):
+
+def check_output(line: str) -> None:
+    """Check log output for expected messages."""
+    if not connected_future.done() and connected_pattern.search(line):
+        connected_future.set_result(True)
+    elif not service_future.done() and service_pattern.search(line):
+        service_future.set_result(True)
+
+
+async with run_compiled(yaml_config, line_callback=check_output):
     async with api_client_connected() as client:
-        await log.wait(connected)
-        match = await log.wait(value, timeout=5.0, msg="no value logged")
-        assert match.group(1) == "42"
-        assert log.count("Service called") == 1
-```
+        # Wait for specific log message
+        await asyncio.wait_for(connected_future, timeout=5.0)
 
-- `expect(pattern)` only matches lines that arrive after the call. A `str` matches as a
-  substring and resolves to the line; a compiled regex is searched and resolves to its match.
-  Each expectation resolves on the next matching line, so two armed for the same text both
-  resolve on its first occurrence: arm the second after the first resolves, or use `count`.
-- `wait(future)` fails the test on timeout with the pattern and the last 20 log lines.
-- `wait_for(*needles)` also matches lines seen before the call, but only one may be pending.
-- `count(pattern)` counts the lines seen so far.
+        # Do test actions...
+
+        # Wait for service log
+        await asyncio.wait_for(service_future, timeout=5.0)
+```
 
 **Note**: Tests that monitor log messages typically have fewer race conditions compared to state-based testing, making them more reliable. However, be aware that the host platform currently does not have a thread-safe logger, so logging from threads will not work correctly.
 

tests/integration/log_utils.py

@@ -3,47 +3,23 @@
 from __future__ import annotations
 
 import asyncio
-import re
-from typing import Any, overload
-
-from .wait_utils import wait_or_fail
-
-type LinePattern = str | re.Pattern[str]
-type LineMatch = str | re.Match[str]
-
-
-def _match(pattern: LinePattern, line: str) -> LineMatch | None:
-    """Return ``line`` if a str pattern is in it, or the search match of a regex."""
-    if isinstance(pattern, str):
-        return line if pattern in line else None
-    return pattern.search(line)
 
 
 class LineWaiter:
-    """Collects log lines and lets a test await lines that match.
+    """Collects log lines and lets a test await one containing all needles.
 
     Pass ``callback`` as ``run_compiled``'s ``line_callback``; the callback runs
-    on the test's own event loop, so futures are resolved directly. ``wait_for``
-    also matches lines seen before the call, and only one may be outstanding at a
-    time. ``expect`` matches only later lines, and any number may be armed at once;
-    each resolves on the next matching line, so two armed for the same text both
-    resolve on its first occurrence. Arm the second after the first, or use ``count``.
+    on the test's own event loop, so futures are resolved directly. Only one
+    ``wait_for`` may be outstanding at a time (tests await sequentially).
     """
 
     def __init__(self) -> None:
         self.lines: list[str] = []
         self._needles: tuple[str, ...] = ()
         self._future: asyncio.Future | None = None
-        self._expectations: dict[asyncio.Future[Any], LinePattern] = {}
 
     def callback(self, line: str) -> None:
         self.lines.append(line)
-        for future, pattern in list(self._expectations.items()):
-            if future.done():
-                del self._expectations[future]
-            elif (match := _match(pattern, line)) is not None:
-                future.set_result(match)
-                del self._expectations[future]
         if (
             self._future is not None
             and not self._future.done()
@@ -70,38 +46,3 @@ class LineWaiter:
         finally:
             self._future = None
             self._needles = ()
-
-    @overload
-    def expect(self, pattern: str) -> asyncio.Future[str]: ...  # noqa: E704
-
-    @overload
-    def expect(self, pattern: re.Pattern[str]) -> asyncio.Future[re.Match[str]]: ...  # noqa: E704
-
-    def expect(self, pattern: LinePattern) -> asyncio.Future[LineMatch]:
-        """Arm a wait for the next line matching ``pattern``; earlier lines never match.
-
-        A str matches as a substring and resolves to the line; a compiled regex is
-        searched and resolves to its match. Arm it before the action that logs the line.
-        """
-        future: asyncio.Future[LineMatch] = asyncio.get_running_loop().create_future()
-        self._expectations[future] = pattern
-        return future
-
-    async def wait[T: str | re.Match[str]](
-        self,
-        future: asyncio.Future[T],
-        timeout: float = 5.0,
-        msg: str = "log line not seen",
-    ) -> T:
-        """Await a future from ``expect``; on timeout fail with its pattern and the last lines."""
-        return await wait_or_fail(
-            future,
-            timeout,
-            msg,
-            pattern=self._expectations.get(future),
-            lines=self.lines,
-        )
-
-    def count(self, pattern: LinePattern) -> int:
-        """Return how many lines seen so far match ``pattern``."""
-        return sum(_match(pattern, line) is not None for line in self.lines)

tests/integration/state_utils.py

@@ -4,7 +4,6 @@ from __future__ import annotations
 
 import asyncio
 from collections.abc import Awaitable, Callable
-from dataclasses import dataclass
 import logging
 from typing import TypeVar
 
@@ -101,22 +100,6 @@ class StateWaiter:
         self._waiters.append(entry)
         return self._wait(entry, timeout, label)
 
-    def next_state[T: EntityState](
-        self,
-        key: int | None = None,
-        state_type: type[T] = EntityState,
-        timeout: float = 5.0,
-    ) -> Awaitable[T]:
-        """Arm a wait for the next ``state_type`` state, for entity ``key`` if given.
-
-        Like :meth:`expect`, call it before sending the command and await the result afterwards.
-        """
-        return self.expect(
-            lambda s: isinstance(s, state_type) and (key is None or s.key == key),
-            timeout,
-            state_type.__name__ if key is None else f"{state_type.__name__} key={key}",
-        )
-
     async def _wait(
         self,
         entry: tuple[Callable[[EntityState], bool], asyncio.Future[EntityState]],
@@ -419,58 +402,6 @@ class InitialStateHelper:
         )
 
 
-@dataclass(frozen=True, slots=True)
-class StateSubscription:
-    """A state subscription that is past the connect time states."""
-
-    initial_states: dict[int, EntityState]
-    waiter: StateWaiter
-
-
-async def subscribe_after_initial_states(
-    client: APIClient,
-    entities: list[EntityInfo],
-    on_state: Callable[[EntityState], None] | None = None,
-    timeout: float = 5.0,
-) -> StateSubscription:
-    """Subscribe to states and wait until every entity has sent its connect time state.
-
-    Later states go to ``on_state`` (if given) and to the returned ``waiter``. The connect time
-    states are kept in ``initial_states`` by key. Fails the test listing the entities still missing.
-    """
-    helper = InitialStateHelper(entities)
-    waiter = StateWaiter()
-
-    def forward(state: EntityState) -> None:
-        waiter.on_state(state)
-        if on_state is not None:
-            on_state(state)
-
-    client.subscribe_states(helper.on_state_wrapper(forward))
-    await helper.wait_for_initial_states(timeout)
-    return StateSubscription(helper.initial_states, waiter)
-
-
-async def press_and_wait[T: EntityState](
-    client: APIClient,
-    entities: list[EntityInfo],
-    waiter: StateWaiter,
-    button: str,
-    state_type: type[T],
-    *,
-    key: int | None = None,
-    timeout: float = 5.0,
-) -> T:
-    """Press the button whose object_id contains ``button`` and return the next ``state_type`` state.
-
-    Pass the entity's ``key`` when the fixture has more than one entity of that type.
-    """
-    btn = require_entity(entities, button, ButtonInfo)
-    next_state = waiter.next_state(key=key, state_type=state_type, timeout=timeout)
-    client.button_command(btn.key)
-    return await next_state
-
-
 class SensorStateCollector:
     """Collects sensor, binary sensor, and text sensor state updates with wait helpers.
 

tests/unit_tests/test_integration_log_utils.py

@@ -1,81 +0,0 @@
-"""Tests for the integration test LineWaiter."""
-
-from __future__ import annotations
-
-import asyncio
-import re
-
-import pytest
-
-from tests.integration.log_utils import LineWaiter
-
-
-@pytest.mark.asyncio
-async def test_expect_matches_only_later_lines() -> None:
-    waiter = LineWaiter()
-    waiter.callback("[I][app]: ready")
-    ready = waiter.expect("ready")
-    value = waiter.expect(re.compile(r"value=(\d+)"))
-    assert not ready.done()
-
-    waiter.callback("[D][x]: value=42")
-    waiter.callback("[I][app]: ready again")
-    assert await waiter.wait(ready) == "[I][app]: ready again"
-    match = await waiter.wait(value)
-    assert isinstance(match, re.Match)
-    assert match.group(1) == "42"
-    # wait_for still matches lines seen before the call.
-    assert await waiter.wait_for("app", "ready") == "[I][app]: ready"
-
-
-@pytest.mark.asyncio
-async def test_wait_timeout_reports_pattern_and_lines() -> None:
-    waiter = LineWaiter()
-    for i in range(30):
-        waiter.callback(f"line {i}")
-    future = waiter.expect("never")
-    with pytest.raises(pytest.fail.Exception) as err:
-        await waiter.wait(future, 0.01, "boot message missing")
-    message = str(err.value)
-    assert message.startswith("boot message missing (after 0.01s)")
-    assert "pattern: 'never'" in message
-    assert "lines (last 20 of 30):" in message
-    assert message.endswith("line 29")
-    assert future.cancelled()
-    # The cancelled expectation is dropped on the next line.
-    waiter.callback("never")
-    assert not waiter._expectations
-
-
-def test_count() -> None:
-    waiter = LineWaiter()
-    for line in ("tick 1", "tock", "tick 2"):
-        waiter.callback(line)
-    assert waiter.count("tick") == 2
-    assert waiter.count(re.compile(r"t\w+k$")) == 1
-    assert waiter.count("missing") == 0
-
-
-@pytest.mark.asyncio
-async def test_expect_resolves_from_callback_while_waiting() -> None:
-    waiter = LineWaiter()
-    first = waiter.expect("first")
-    second = waiter.expect("second")
-    loop = asyncio.get_running_loop()
-    loop.call_soon(waiter.callback, "second")
-    loop.call_soon(waiter.callback, "first")
-    assert await waiter.wait(first) == "first"
-    assert await waiter.wait(second) == "second"
-
-
-@pytest.mark.asyncio
-async def test_line_waiter_expectations_share_a_matching_line() -> None:
-    waiter = LineWaiter()
-    first = waiter.expect("tick")
-    second = waiter.expect("tick")
-    waiter.callback("tick 1")
-    assert first.result() == second.result() == "tick 1"
-    third = waiter.expect("tick")
-    waiter.callback("tick 2")
-    assert third.result() == "tick 2"
-    assert waiter.count("tick") == 2

tests/unit_tests/test_integration_state_subscribe.py

@@ -1,108 +0,0 @@
-"""Tests for the state subscription helpers in tests/integration/state_utils.py."""
-
-from __future__ import annotations
-
-import asyncio
-from collections.abc import Callable
-
-from aioesphomeapi import ButtonInfo, EntityState, SensorInfo, SensorState, SwitchState
-import pytest
-
-from tests.integration.state_utils import (
-    StateSubscription,
-    StateWaiter,
-    press_and_wait,
-    subscribe_after_initial_states,
-)
-
-ENTITIES = [
-    SensorInfo(object_id="temp", key=1),
-    SensorInfo(object_id="humidity", key=2),
-    ButtonInfo(object_id="set_temp", key=3),
-]
-
-
-class FakeClient:
-    """Records the state callback and button presses."""
-
-    def __init__(self) -> None:
-        self.callback: Callable[[EntityState], None] | None = None
-        self.pressed: list[int] = []
-
-    def subscribe_states(self, callback: Callable[[EntityState], None]) -> None:
-        self.callback = callback
-
-    def button_command(self, key: int) -> None:
-        self.pressed.append(key)
-        self.callback(SensorState(key=1, state=42.0))
-
-
-async def _subscribe(client: FakeClient, **kwargs: object) -> StateSubscription:
-    task = asyncio.create_task(
-        subscribe_after_initial_states(client, ENTITIES, **kwargs)
-    )
-    await asyncio.sleep(0)
-    client.callback(SensorState(key=1, state=1.0))
-    client.callback(SensorState(key=2, state=2.0))
-    return await task
-
-
-@pytest.mark.asyncio
-async def test_subscribe_swallows_initial_states_and_forwards_later_ones() -> None:
-    client = FakeClient()
-    received: list[EntityState] = []
-    sub = await _subscribe(client, on_state=received.append)
-    assert sub.initial_states[1].state == 1.0
-    assert sub.initial_states[2].state == 2.0
-    assert received == []
-
-    next_state = sub.waiter.next_state(key=2, state_type=SensorState)
-    client.callback(SensorState(key=1, state=3.0))
-    client.callback(SensorState(key=2, state=4.0))
-    assert (await next_state).state == 4.0
-    assert [s.state for s in received] == [3.0, 4.0]
-
-
-@pytest.mark.asyncio
-async def test_subscribe_timeout_lists_missing_entities() -> None:
-    client = FakeClient()
-    task = asyncio.create_task(
-        subscribe_after_initial_states(client, ENTITIES, timeout=0.01)
-    )
-    await asyncio.sleep(0)
-    client.callback(SensorState(key=1, state=1.0))
-    with pytest.raises(pytest.fail.Exception, match=r"still_waiting[\s\S]*humidity"):
-        await task
-
-
-@pytest.mark.asyncio
-async def test_next_state_filters_by_type_and_times_out() -> None:
-    waiter = StateWaiter()
-    next_switch = waiter.next_state(state_type=SwitchState)
-    waiter.on_state(SensorState(key=1, state=1.0))
-    waiter.on_state(SwitchState(key=5, state=True))
-    assert (await next_switch).key == 5
-    with pytest.raises(TimeoutError, match="SwitchState key=9"):
-        await waiter.next_state(key=9, state_type=SwitchState, timeout=0.01)
-
-
-@pytest.mark.asyncio
-async def test_press_and_wait_presses_button_and_returns_state() -> None:
-    client = FakeClient()
-    sub = await _subscribe(client)
-    state = await press_and_wait(client, ENTITIES, sub.waiter, "set_temp", SensorState)
-    assert client.pressed == [3]
-    assert state.state == 42.0
-
-
-@pytest.mark.asyncio
-async def test_press_and_wait_waits_for_the_given_key() -> None:
-    client = FakeClient()
-    sub = await _subscribe(client)
-    pending = asyncio.ensure_future(
-        press_and_wait(client, ENTITIES, sub.waiter, "set_temp", SensorState, key=2)
-    )
-    await asyncio.sleep(0)
-    assert not pending.done()  # the press published key 1
-    client.callback(SensorState(key=2, state=55.0))
-    assert (await pending).state == 55.0