Warn for old slugs/entity ids (#20478)

* Warn for old slugs/entity ids

* add comments

* Lint

* LInt

* Lint

* Lint

tests/helpers/test_config_validation.py

@@ -602,3 +602,31 @@ def test_comp_entity_ids():
     for invalid in (['light.kitchen', 'not-entity-id'], '*', ''):
         with pytest.raises(vol.Invalid):
             schema(invalid)
+
+
+def test_schema_with_slug_keys_allows_old_slugs(caplog):
+    """Test schema with slug keys allowing old slugs."""
+    schema = cv.schema_with_slug_keys(str)
+
+    with patch.dict(cv.INVALID_SLUGS_FOUND, clear=True):
+        for value in ('_world', 'wow__yeah'):
+            caplog.clear()
+            # Will raise if not allowing old slugs
+            schema({value: 'yo'})
+            assert "Found invalid slug {}".format(value) in caplog.text
+
+        assert len(cv.INVALID_SLUGS_FOUND) == 2
+
+
+def test_entity_id_allow_old_validation(caplog):
+    """Test schema allowing old entity_ids."""
+    schema = vol.Schema(cv.entity_id)
+
+    with patch.dict(cv.INVALID_ENTITY_IDS_FOUND, clear=True):
+        for value in ('hello.__world', 'great.wow__yeah'):
+            caplog.clear()
+            # Will raise if not allowing old entity ID
+            schema(value)
+            assert "Found invalid entity_id {}".format(value) in caplog.text
+
+        assert len(cv.INVALID_ENTITY_IDS_FOUND) == 2