[usb_uart] Only compile the vendor drivers that are configured (#20190)

tests/component_tests/usb_uart/test_source_filter.py

@@ -0,0 +1,19 @@
+"""Tests for the usb_uart component's driver source filtering."""
+
+from collections.abc import Callable
+
+from esphome.core import CORE
+
+
+def test_only_configured_driver_compiled(
+    generate_main: Callable[[str], str],
+) -> None:
+    generate_main("tests/component_tests/usb_uart/test_usb_uart_ft232.yaml")
+    from esphome.components.usb_uart import FILTER_SOURCE_FILES
+
+    defines = {define.name for define in CORE.defines}
+    # cdc_acm is built into usb_uart.cpp and adds no driver define
+    assert {d for d in defines if d.startswith("USE_USB_UART_")} == {
+        "USE_USB_UART_FT23XX"
+    }
+    assert sorted(FILTER_SOURCE_FILES()) == ["ch34x.cpp", "cp210x.cpp", "pl2303.cpp"]

tests/component_tests/usb_uart/test_usb_uart_ft232.yaml

@@ -0,0 +1,18 @@
+esphome:
+  name: test
+
+esp32:
+  variant: esp32s3
+  framework:
+    type: esp-idf
+
+usb_uart:
+  - type: ft232
+    channels:
+      - id: ft_channel
+        baud_rate: 115200
+  - type: cdc_acm
+    vid: 0x1234
+    pid: 0x5678
+    channels:
+      - id: cdc_channel