[store_yaml] Add coverage for gated YAML discovery in load_config

tests/unit_tests/test_config_normalization.py

@@ -151,6 +151,27 @@ def test_validate_config_warns_on_dropped_merge_key(
     assert yaml_util.take_dropped_merge_keys() == []
 
 
+@pytest.mark.parametrize("store_yaml_enabled", [False, True])
+def test_load_config_gates_yaml_discovery_on_store_yaml(
+    tmp_path: Path, store_yaml_enabled: bool
+) -> None:
+    """YAML source discovery (a second full parse) only runs when a consumer
+    like store_yaml is configured."""
+    content = "esphome:\n  name: test\nhost:\napi:\n"
+    if store_yaml_enabled:
+        content += "store_yaml:\n  allow_unencrypted: true\n"
+    main = tmp_path / "main.yaml"
+    main.write_text(content)
+    CORE.config_path = main
+
+    result = config.load_config({})
+
+    assert not result.errors
+    assert ("yaml_sources" in CORE.data) == store_yaml_enabled
+    if store_yaml_enabled:
+        assert main.resolve() in CORE.data["yaml_sources"].files
+
+
 def test_validate_config_suppresses_merge_warning(
     tmp_path: Path, caplog: pytest.LogCaptureFixture
 ) -> None: