diff --git a/esphome/__main__.py b/esphome/__main__.py
index e5f8110bc6..25ff986b0b 100644
--- a/esphome/__main__.py
+++ b/esphome/__main__.py
@@ -865,11 +865,8 @@ def compile_program(args: ArgsProtocol, config: ConfigType) -> int:
             RuntimeError,
             ValueError,
         ) as err:
-            # The firmware already built; idedata is a bonus artifact here.
-            # Broad on purpose: a vanished compiler (OSError), a failed
-            # include probe (RuntimeError), or a truncated compile DB
-            # (ValueError/LookupError) must not fail a successful build
-            # either.
+            # Broad on purpose: the firmware already built; an idedata
+            # failure must not fail a successful build.
             _LOGGER.warning("Could not generate idedata: %s", err)
     else:
         from esphome.platformio import toolchain
diff --git a/esphome/build_helpers/idedata.py b/esphome/build_helpers/idedata.py
index 31b62df528..00a890e087 100644
--- a/esphome/build_helpers/idedata.py
+++ b/esphome/build_helpers/idedata.py
@@ -123,10 +123,8 @@ def _pick_entry(entries: list[dict]) -> dict:
     raise ValueError("no C++ translation unit found in compile_commands.json")
 
 
-# Compiler launchers that may prefix a compile command. A closed denylist is
-# sturdier than trying to enumerate compiler names: launchers are few and
-# stable, while compilers (cross prefixes, versioned names, icx, armcc, ...)
-# are an open set.
+# Compiler launchers that may prefix a compile command; a closed launcher
+# denylist beats enumerating compiler names, an open set.
 _LAUNCHER_STEMS = frozenset({"ccache", "sccache", "distcc", "icecc", "buildcache"})
 
 
@@ -300,17 +298,14 @@ def idedata_from_build(compile_commands: Path, launcher: str | None = None) -> d
     representative = _pick_entry(entries)
     cxx_path, defines, rep_includes, cxx_flags = parse_entry(representative, launcher)
     if _is_launcher(cxx_path):
-        # Checked before the toolchain probe (which would fail opaquely on
-        # a launcher) so the unusable compile DB is named, and never
-        # cached or conflated with "nothing built yet"
+        # Reject before the toolchain probe, which would fail opaquely on
+        # a launcher; never cache the unusable compile DB
         raise EsphomeError(
             f"compile_commands.json names the launcher {cxx_path} as the "
             "compiler; the compile database is unusable"
         )
 
     # Seed with the representative's includes so it is not parsed twice
-    # (per-file -c/-o arguments make every command distinct, so memoizing
-    # whole commands would never hit)
     build_includes: dict[str, None] = dict.fromkeys(
         rep_includes if _is_esphome_src(representative["file"]) else ()
     )
diff --git a/esphome/build_helpers/size_summary.py b/esphome/build_helpers/size_summary.py
index 72c429d095..b888111044 100644
--- a/esphome/build_helpers/size_summary.py
+++ b/esphome/build_helpers/size_summary.py
@@ -4,11 +4,7 @@ from __future__ import annotations
 
 
 def format_bar(used: int, total: int) -> str:
-    """Match PlatformIO's ``_format_availale_bytes`` (pioupload.py) exactly.
-
-    The upstream helper's name really is spelled that way; keep the citation
-    verbatim so it stays greppable in the PlatformIO source.
-    """
+    """Match PlatformIO's ``_format_availale_bytes`` (sic, pioupload.py) exactly."""
     pct_raw = used / total if total else 0
     blocks = 10
     filled = min(int(round(blocks * pct_raw)), blocks)
diff --git a/esphome/espidf/component.py b/esphome/espidf/component.py
index 07c3dc9dde..567cde65e2 100644
--- a/esphome/espidf/component.py
+++ b/esphome/espidf/component.py
@@ -92,10 +92,8 @@ def generate_cmakelists_txt(component: IDFComponent) -> str:
     build_flags = ensure_list(
         component.data.get("build", {}).get("flags", DEFAULT_BUILD_FLAGS)
     )
-    # PlatformIO shell-lexes each build.flags entry, so one entry can carry a
-    # flag and its argument (e.g. "-include cp_custom_alloc.h"); bare
-    # -I/-L/-l/-D tokens re-glue to their argument ("-I foo" -> "-Ifoo") so
-    # prefix classifiers below still route them.
+    # PlatformIO shell-lexes each build.flags entry; bare -I/-L/-l/-D tokens
+    # re-glue to their argument so the prefix classifiers below route them.
     # Joined per entry, as SCons's ParseFlags lexes each string
     # independently: a dangling -I ending one entry must warn, not absorb
     # the next entry's first token.
diff --git a/esphome/platformio/extra_script.py b/esphome/platformio/extra_script.py
index 4a0a0dc7c5..e311e8729b 100644
--- a/esphome/platformio/extra_script.py
+++ b/esphome/platformio/extra_script.py
@@ -141,9 +141,7 @@ class _FakeSConsEnv:
     def Append(self, **kwargs) -> None:  # noqa: N802 (SCons API name)
         for key, value in kwargs.items():
             if key not in _CAPTURED_KEYS:
-                # Diagnosable from the build log when a script configures
-                # something this shim does not translate; once per key so a
-                # loop of Appends cannot spam
+                # Warn once per key so a loop of Appends cannot spam
                 if key not in self._warned_keys:
                     self._warned_keys.add(key)
                     _LOGGER.warning(
@@ -239,9 +237,8 @@ def run_extra_script(
         )
         return ExtraScriptResult()
     except Exception as e:  # noqa: BLE001  # pylint: disable=broad-exception-caught
-        # Discard any partial capture: folding half a script's flags into the
-        # build could produce wrong-output firmware that links cleanly. The
-        # warning plus the resulting loud link error point back here.
+        # Discard any partial capture: half-applied flags could build wrong
+        # firmware that links cleanly.
         _LOGGER.warning(
             "PIO extra-script %s (in %s) raised %r; ignoring its output",
             script_path,
diff --git a/esphome/platformio/library.py b/esphome/platformio/library.py
index e93d9c499f..7ce45a7fca 100644
--- a/esphome/platformio/library.py
+++ b/esphome/platformio/library.py
@@ -47,11 +47,8 @@ DEFAULT_BUILD_SRC_FILTER = (
 DEFAULT_BUILD_SRC_DIRS = "src"
 DEFAULT_BUILD_INCLUDE_DIR = "include"
 DEFAULT_BUILD_FLAGS = []
-# Source suffix -> compiler kind, PlatformIO's CSUFFIXES/CXXSUFFIXES/ASSUFFIXES
-# split. Native build generators map the kind to their compile rules. "asm"
-# deliberately merges SCons's AS (.s/.asm) and ASPP (.S/.spp/.sx) sets: the
-# ninja rules compile all of them as assembler-with-cpp, whose asm-mode
-# preprocessor passes non-directive text through unchanged.
+# Suffix -> compiler kind (PlatformIO's CSUFFIXES/CXXSUFFIXES/ASSUFFIXES).
+# "asm" merges SCons's AS and ASPP sets: all compile as assembler-with-cpp.
 SOURCE_KIND_FOR_SUFFIX: dict[str, str] = {
     ".c": "c",
     ".cpp": "cxx",
diff --git a/tests/unit_tests/build_helpers/test_idedata.py b/tests/unit_tests/build_helpers/test_idedata.py
index 7297912955..52ffc88224 100644
--- a/tests/unit_tests/build_helpers/test_idedata.py
+++ b/tests/unit_tests/build_helpers/test_idedata.py
@@ -429,8 +429,7 @@ def test_load_or_build_idedata_corrupted_cache_is_logged(
 
 
 def test_load_or_build_idedata_never_caches_a_launcher(tmp_path: Path) -> None:
-    """A compile DB naming a launcher as the compiler is rejected by name,
-    before the toolchain probe could fail opaquely, and never cached."""
+    """A compile DB naming a launcher as the compiler is rejected, never cached."""
     compile_commands = tmp_path / "compile_commands.json"
     compile_commands.write_text(
         json.dumps(
diff --git a/tests/unit_tests/test_espidf_component.py b/tests/unit_tests/test_espidf_component.py
index 1baa22777c..e2884454e5 100644
--- a/tests/unit_tests/test_espidf_component.py
+++ b/tests/unit_tests/test_espidf_component.py
@@ -6,6 +6,7 @@ from unittest.mock import MagicMock
 
 import pytest
 
+from esphome.components import esp32 as esp32_module
 from esphome.const import (
     KEY_CORE,
     KEY_TARGET_FRAMEWORK,
@@ -15,6 +16,7 @@ from esphome.const import (
 )
 from esphome.core import CORE, Library
 from esphome.espidf.component import (
+    _emit_idf_component,
     generate_cmakelists_txt,
     generate_idf_component_yml,
     generate_idf_components,
@@ -1072,8 +1074,6 @@ def test_idf_component_download_passes_salt() -> None:
 def test_emit_idf_component_wires_esp32_target(tmp_path, monkeypatch):
     """Emitting a component resolves the esp32 variant into the shared
     extraScript helper."""
-    from esphome.components import esp32 as esp32_module
-    from esphome.espidf.component import _emit_idf_component
 
     monkeypatch.setattr(esp32_module, "get_esp32_variant", lambda: "ESP32")
     (tmp_path / "src").mkdir()
diff --git a/tests/unit_tests/test_main.py b/tests/unit_tests/test_main.py
index b0cb5f6a0a..d20832af6b 100644
--- a/tests/unit_tests/test_main.py
+++ b/tests/unit_tests/test_main.py
@@ -101,6 +101,7 @@ from esphome.const import (
     CONF_WEB_SERVER,
     CONF_WIFI,
     KEY_CORE,
+    KEY_TARGET_FRAMEWORK,
     KEY_TARGET_PLATFORM,
     PLATFORM_BK72XX,
     PLATFORM_ESP32,
@@ -7139,7 +7140,7 @@ def test_warn_source_tree_mismatch_falls_back_when_stat_fails(
         RuntimeError("Could not query builtin include dirs"),
         ValueError("no C++ translation unit found"),
         KeyError("command"),
-        None,  # replaced with EsphomeError inside (import is function-local)
+        None,  # replaced with EsphomeError inside
     ],
 )
 def test_compile_program_espidf_idedata_failure_does_not_fail_build(
@@ -7147,14 +7148,6 @@ def test_compile_program_espidf_idedata_failure_does_not_fail_build(
     caplog: pytest.LogCaptureFixture,
 ) -> None:
     """A post-compile idedata error is a warning: the firmware already built."""
-    from esphome.const import (
-        KEY_CORE,
-        KEY_TARGET_FRAMEWORK,
-        KEY_TARGET_PLATFORM,
-        Toolchain,
-    )
-    from esphome.core import CORE, EsphomeError
-
     if error is None:
         error = EsphomeError("compile database is unusable")
     CORE.toolchain = Toolchain.ESP_IDF
@@ -7178,14 +7171,6 @@ def test_compile_program_espidf_idedata_success_is_silent(
     caplog: pytest.LogCaptureFixture,
 ) -> None:
     """The healthy path: idedata generated, nothing to warn about."""
-    from esphome.const import (
-        KEY_CORE,
-        KEY_TARGET_FRAMEWORK,
-        KEY_TARGET_PLATFORM,
-        Toolchain,
-    )
-    from esphome.core import CORE
-
     CORE.toolchain = Toolchain.ESP_IDF
     CORE.data[KEY_CORE] = {
         KEY_TARGET_PLATFORM: "esp32",
@@ -7207,14 +7192,6 @@ def test_compile_program_espidf_idedata_none_warns(
     caplog: pytest.LogCaptureFixture,
 ) -> None:
     """A silent None from the post-compile idedata refresh is made visible."""
-    from esphome.const import (
-        KEY_CORE,
-        KEY_TARGET_FRAMEWORK,
-        KEY_TARGET_PLATFORM,
-        Toolchain,
-    )
-    from esphome.core import CORE
-
     CORE.toolchain = Toolchain.ESP_IDF
     CORE.data[KEY_CORE] = {
         KEY_TARGET_PLATFORM: "esp32",
diff --git a/tests/unit_tests/test_platformio_extra_script.py b/tests/unit_tests/test_platformio_extra_script.py
index 7e904183f1..d09f02d95f 100644
--- a/tests/unit_tests/test_platformio_extra_script.py
+++ b/tests/unit_tests/test_platformio_extra_script.py
@@ -2,19 +2,25 @@
 
 from __future__ import annotations
 
+import logging
 import os
 from pathlib import Path
+from unittest.mock import patch
 
 import pytest
 
+from esphome.core import EsphomeError
+from esphome.platformio.extra_script import (
+    ExtraScriptResult,
+    _FakeSConsEnv,
+    apply_extra_script,
+    captured_as_build_flags,
+    run_extra_script,
+)
 from esphome.platformio.library import ConvertedLibrary as IDFComponent, URLSource
 
 
 def test_extra_script_captures_libpath_libs_and_defines(tmp_path):
-    from esphome.platformio.extra_script import (
-        captured_as_build_flags,
-        run_extra_script,
-    )
 
     (tmp_path / "src" / "esp32").mkdir(parents=True)
     script = tmp_path / "extra_script.py"
@@ -58,10 +64,6 @@ def test_extra_script_libpath_relative_resolves_against_library_dir(
     """Relative LIBPATH entries must resolve against ``library_dir``, not the
     caller's CWD (the shim restores CWD before ``captured_as_build_flags``
     runs)."""
-    from esphome.platformio.extra_script import (
-        ExtraScriptResult,
-        captured_as_build_flags,
-    )
 
     (tmp_path / "lib" / "esp32").mkdir(parents=True)
     elsewhere = tmp_path.parent / "not_the_library_dir"
@@ -76,10 +78,6 @@ def test_extra_script_libpath_relative_resolves_against_library_dir(
 
 
 def test_extra_script_libpath_absolute_outside_library_dir(tmp_path):
-    from esphome.platformio.extra_script import (
-        ExtraScriptResult,
-        captured_as_build_flags,
-    )
 
     outside = tmp_path.parent / "system_lib"
     outside.mkdir(exist_ok=True)
@@ -90,7 +88,6 @@ def test_extra_script_libpath_absolute_outside_library_dir(tmp_path):
 
 
 def test_extra_script_failure_returns_empty_result(tmp_path, caplog):
-    from esphome.platformio.extra_script import run_extra_script
 
     script = tmp_path / "broken.py"
     script.write_text("raise RuntimeError('boom')\n")
@@ -106,7 +103,6 @@ def test_extra_script_failure_returns_empty_result(tmp_path, caplog):
 
 
 def test_apply_extra_script_path_traversal_is_rejected(tmp_path):
-    from esphome.platformio.extra_script import apply_extra_script
 
     library_dir = tmp_path / "lib"
     library_dir.mkdir()
@@ -117,8 +113,6 @@ def test_apply_extra_script_path_traversal_is_rejected(tmp_path):
     c.path = library_dir
     c.data = {"build": {"extraScript": "../evil.py"}}
 
-    from esphome.core import EsphomeError
-
     with pytest.raises(EsphomeError, match="escapes the library directory"):
         apply_extra_script(c, board_mcu=lambda: "esp32", pio_platform="espressif32")
     # Nothing was folded into flags: the traversal was rejected before
@@ -127,7 +121,6 @@ def test_apply_extra_script_path_traversal_is_rejected(tmp_path):
 
 
 def test_apply_extra_script_merges_into_existing_flags(tmp_path):
-    from esphome.platformio.extra_script import apply_extra_script
 
     (tmp_path / "src").mkdir()
     script = tmp_path / "extra.py"
@@ -146,8 +139,6 @@ def test_apply_extra_script_merges_into_existing_flags(tmp_path):
 def test_apply_extra_script_malformed_flags_raises(tmp_path) -> None:
     """A null/dict build.flags fails naming the library instead of injecting
     a non-string into the compiler command line."""
-    from esphome.core import EsphomeError
-    from esphome.platformio.extra_script import apply_extra_script
 
     (tmp_path / "src").mkdir()
     script = tmp_path / "extra.py"
@@ -164,7 +155,6 @@ def test_apply_extra_script_malformed_flags_raises(tmp_path) -> None:
 def test_apply_extra_script_callable_target_and_str_flags(tmp_path) -> None:
     """The shared helper resolves the board_mcu callable lazily and normalizes
     a string ``build.flags`` value into a list before extending it."""
-    from esphome.platformio.extra_script import apply_extra_script
 
     (tmp_path / "src").mkdir()
     script = tmp_path / "extra.py"
@@ -180,7 +170,6 @@ def test_apply_extra_script_callable_target_and_str_flags(tmp_path) -> None:
 
 
 def test_apply_extra_script_no_script_and_no_flags(tmp_path) -> None:
-    from esphome.platformio.extra_script import apply_extra_script
 
     # No extraScript declared: nothing happens, the target is never resolved
     c = IDFComponent("owner/name", "1.0", source=URLSource("http://dummy"))
@@ -203,9 +192,6 @@ def test_apply_extra_script_no_script_and_no_flags(tmp_path) -> None:
 def test_apply_extra_script_ignores_uncaptured_env_calls(tmp_path, caplog) -> None:
     """Un-captured env vars and unsupported env methods are skipped but
     diagnosable from the build log."""
-    import logging
-
-    from esphome.platformio.extra_script import apply_extra_script
 
     caplog.set_level(logging.DEBUG)
     script = tmp_path / "extra.py"
@@ -223,7 +209,6 @@ def test_apply_extra_script_ignores_uncaptured_env_calls(tmp_path, caplog) -> No
 
 def test_apply_extra_script_swallows_script_errors(tmp_path, caplog) -> None:
     """A raising extra-script is best-effort: logged and skipped."""
-    from esphome.platformio.extra_script import apply_extra_script
 
     script = tmp_path / "extra.py"
     script.write_text("raise RuntimeError('boom')\n")
@@ -237,7 +222,6 @@ def test_apply_extra_script_swallows_script_errors(tmp_path, caplog) -> None:
 
 def test_apply_extra_script_pio_platform(tmp_path) -> None:
     """The backend's platform token is exposed to the script as PIOPLATFORM."""
-    from esphome.platformio.extra_script import apply_extra_script
 
     script = tmp_path / "extra.py"
     script.write_text("env.Append(LIBS=[env.get('PIOPLATFORM')])\n")
@@ -251,8 +235,6 @@ def test_apply_extra_script_pio_platform(tmp_path) -> None:
 def test_apply_extra_script_missing_script_raises(tmp_path) -> None:
     """A declared but absent extraScript is a broken package and fails by
     name, as it would under PlatformIO."""
-    from esphome.core import EsphomeError
-    from esphome.platformio.extra_script import apply_extra_script
 
     c = IDFComponent("owner/name", "1.0", source=URLSource("http://dummy"))
     c.path = tmp_path
@@ -264,7 +246,6 @@ def test_apply_extra_script_missing_script_raises(tmp_path) -> None:
 def test_run_extra_script_failure_discards_partial_capture(tmp_path, caplog) -> None:
     """A crashed script yields an empty result: half-applied flags could
     build wrong-output firmware that links cleanly."""
-    from esphome.platformio.extra_script import run_extra_script
 
     script = tmp_path / "extra.py"
     script.write_text("env.Append(LIBS=['algobsec'])\nraise RuntimeError('boom')\n")
@@ -278,7 +259,6 @@ def test_run_extra_script_failure_discards_partial_capture(tmp_path, caplog) ->
 def test_run_extra_script_syntax_error_is_best_effort(tmp_path, caplog) -> None:
     """A vendored script that does not even compile warns and skips instead
     of aborting the build."""
-    from esphome.platformio.extra_script import run_extra_script
 
     script = tmp_path / "extra.py"
     script.write_text("def broken(:\n")
@@ -291,7 +271,6 @@ def test_run_extra_script_syntax_error_is_best_effort(tmp_path, caplog) -> None:
 
 def test_unsupported_env_method_warns_once(caplog) -> None:
     """Repeated calls to the same unsupported method warn only once."""
-    from esphome.platformio.extra_script import _FakeSConsEnv
 
     env = _FakeSConsEnv(
         board_mcu="esp8266", pio_env="esphome_esp8266", pio_platform="espressif8266"
@@ -304,7 +283,6 @@ def test_unsupported_env_method_warns_once(caplog) -> None:
 def test_run_extra_script_sys_exit_is_best_effort(tmp_path, caplog) -> None:
     """A nonzero sys.exit() in a vendored script must not kill the esphome
     run, and its output is discarded."""
-    from esphome.platformio.extra_script import run_extra_script
 
     script = tmp_path / "extra.py"
     script.write_text("import sys\nenv.Append(LIBS=['x'])\nsys.exit(3)\n")
@@ -317,7 +295,6 @@ def test_run_extra_script_sys_exit_is_best_effort(tmp_path, caplog) -> None:
 
 def test_run_extra_script_sys_exit_zero_is_success(tmp_path, caplog) -> None:
     """sys.exit(0) is a normal PlatformIO script ending: the capture is kept."""
-    from esphome.platformio.extra_script import run_extra_script
 
     script = tmp_path / "extra.py"
     script.write_text("import sys\nenv.Append(LIBS=['algobsec'])\nsys.exit(0)\n")
@@ -330,10 +307,6 @@ def test_run_extra_script_sys_exit_zero_is_success(tmp_path, caplog) -> None:
 
 def test_run_extra_script_unreadable_raises(tmp_path) -> None:
     """An unreadable declared script is a broken package, like a missing one."""
-    from unittest.mock import patch
-
-    from esphome.core import EsphomeError
-    from esphome.platformio.extra_script import run_extra_script
 
     script = tmp_path / "extra.py"
     script.write_text("")
@@ -348,7 +321,6 @@ def test_run_extra_script_unreadable_raises(tmp_path) -> None:
 
 def test_run_extra_script_bad_encoding_is_best_effort(tmp_path, caplog) -> None:
     """Undecodable content warns and skips, like a SyntaxError."""
-    from esphome.platformio.extra_script import run_extra_script
 
     script = tmp_path / "extra.py"
     script.write_bytes(b"\xff\xfe\x00bad")
@@ -361,7 +333,6 @@ def test_run_extra_script_bad_encoding_is_best_effort(tmp_path, caplog) -> None:
 
 def test_uncaptured_append_key_warns_once(caplog) -> None:
     """A loop of Appends to the same uncaptured key warns once."""
-    from esphome.platformio.extra_script import _FakeSConsEnv
 
     env = _FakeSConsEnv(
         board_mcu="esp8266", pio_env="esphome_esp8266", pio_platform="espressif8266"
diff --git a/tests/unit_tests/test_platformio_library.py b/tests/unit_tests/test_platformio_library.py
index 9567ab985f..d050acad9e 100644
--- a/tests/unit_tests/test_platformio_library.py
+++ b/tests/unit_tests/test_platformio_library.py
@@ -13,6 +13,7 @@ import pytest
 from esphome.core import EsphomeError, Library
 import esphome.platformio.library as lib
 from esphome.platformio.library import (
+    SOURCE_KIND_FOR_SUFFIX,
     ConvertedLibrary,
     GitSource,
     InvalidLibrary,
@@ -23,6 +24,8 @@ from esphome.platformio.library import (
     _resolve_registry_version,
     check_library_data,
     convert_libraries,
+    join_flag_args,
+    split_flag_entry,
 )
 
 
@@ -535,7 +538,6 @@ def test_convert_libraries_skips_incompatible_dependency(tmp_path, monkeypatch):
 
 def test_split_flag_entry_unbalanced_quote_is_clean() -> None:
     """A malformed flags entry raises EsphomeError, not a raw ValueError."""
-    from esphome.platformio.library import split_flag_entry
 
     assert split_flag_entry('-DX="a b"', "library x") == ["-DX=a b"]
     with pytest.raises(EsphomeError, match=r"Malformed build flag.*library x"):
@@ -544,7 +546,6 @@ def test_split_flag_entry_unbalanced_quote_is_clean() -> None:
 
 def test_join_flag_args_reglues_spaced_define() -> None:
     """A spaced -D re-glues to its argument, as ParseFlags does."""
-    from esphome.platformio.library import join_flag_args
 
     assert join_flag_args(["-D", "FOO=1", "-Os"], "x") == ["-DFOO=1", "-Os"]
 
@@ -552,7 +553,6 @@ def test_join_flag_args_reglues_spaced_define() -> None:
 def test_join_flag_args_trailing_bare_flag_warns(
     caplog: pytest.LogCaptureFixture,
 ) -> None:
-    from esphome.platformio.library import join_flag_args
 
     assert join_flag_args(["-Os", "-l"], "library x") == ["-Os"]
     assert "Ignoring trailing '-l'" in caplog.text
@@ -561,7 +561,6 @@ def test_join_flag_args_trailing_bare_flag_warns(
 def test_split_flag_entry_non_string_is_clean() -> None:
     """A dict or number from a third-party manifest fails naming the entry,
     not with an opaque shlex traceback."""
-    from esphome.platformio.library import split_flag_entry
 
     with pytest.raises(EsphomeError, match="Malformed build flag"):
         split_flag_entry({"esp32": ["-DX"]}, "lib x")
@@ -572,7 +571,6 @@ def test_split_flag_entry_non_string_is_clean() -> None:
 def test_source_kind_map_shape() -> None:
     """The kind values the native compile rules key on, and the deliberate
     AS/ASPP merge (.s and .S both map to asm)."""
-    from esphome.platformio.library import SOURCE_KIND_FOR_SUFFIX
 
     assert set(SOURCE_KIND_FOR_SUFFIX.values()) == {"c", "cxx", "asm"}
     assert SOURCE_KIND_FOR_SUFFIX[".s"] == "asm"