Point analyze-memory at the platformio escape hatch, test the backend-table invariant instead of asserting at import, fail blank component lists under the flag, clean the arduino idedata cache

tests/script/test_test_build_components.py

@@ -273,6 +273,18 @@ def test_components_component_with_no_base_file_fails_with_flag(
     )
 
 
+def test_components_blank_list_fails_with_flag(
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """A fully blank component list must not slide into the baseline
+    fallback and exit green under the flag."""
+    rc = tbc.test_components(
+        [""], "esp8266-ard", "compile", False, fail_on_no_tests=True
+    )
+    assert rc == 1
+    assert "blank component list" in capsys.readouterr().out
+
+
 def test_components_empty_match_tolerated_without_flag() -> None:
     """The esp32-ard smoke leg deliberately builds only the subset with a
     matching fixture; without the flag an empty match stays green."""

tests/unit_tests/test_main.py

@@ -7390,6 +7390,15 @@ def test_compile_program_espidf_idedata_none_warns(
     assert "No idedata was generated" in caplog.text
 
 
+def test_native_toolchain_table_serves_every_native_toolchain() -> None:
+    """Every member of NATIVE_TOOLCHAINS has a backend entry; a gap would
+    surface as a targeted EsphomeError on the one affected config, and this
+    pin keeps the table from drifting when a toolchain is added."""
+    from esphome.const import NATIVE_TOOLCHAINS
+
+    assert {tc for _, tc in main._NATIVE_TOOLCHAIN_MODULES} == set(NATIVE_TOOLCHAINS)
+
+
 def test_native_toolchain_module_missing_backend_raises(tmp_path: Path) -> None:
     """A native toolchain missing from the backend table is a bug and must
     fail, not silently degrade to the PlatformIO path."""

tests/unit_tests/test_writer.py

@@ -517,10 +517,13 @@ def test_clean_build(
     dependencies_lock = tmp_path / "dependencies.lock"
     dependencies_lock.write_text("lock file")
 
-    # idedata cache lives under the data dir, not the build path.
+    # idedata caches live under the data dir, not the build path; the
+    # .arduino.json variant is the native esp8266 toolchain's.
     idedata_cache = tmp_path / "idedata" / "test.json"
     idedata_cache.parent.mkdir()
     idedata_cache.write_text("{}")
+    arduino_idedata_cache = tmp_path / "idedata" / "test.arduino.json"
+    arduino_idedata_cache.write_text("{}")
 
     # Native ESP-IDF toolchain artifacts.
     idf_build_dir = tmp_path / "build"
@@ -581,6 +584,7 @@ def test_clean_build(
     assert not piolibdeps_dir.exists()
     assert not dependencies_lock.exists()
     assert not idedata_cache.exists()
+    assert not arduino_idedata_cache.exists()
     assert not idf_build_dir.exists()
     assert not managed_components_dir.exists()
     assert not pio_components_dir.exists()