Add datetime platform (#81943)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>
Co-authored-by: Franck Nijhof <git@frenck.dev>

tests/testing_config/custom_components/test/datetime.py

@@ -0,0 +1,50 @@
+"""Provide a mock time platform.
+
+Call init before using it in your tests to ensure clean test data.
+"""
+from datetime import datetime, timezone
+
+from homeassistant.components.datetime import DateTimeEntity
+
+from tests.common import MockEntity
+
+UNIQUE_DATETIME = "unique_datetime"
+
+ENTITIES = []
+
+
+class MockDateTimeEntity(MockEntity, DateTimeEntity):
+    """Mock date/time class."""
+
+    @property
+    def native_value(self):
+        """Return the native value of this date/time."""
+        return self._handle("native_value")
+
+    def set_value(self, value: datetime) -> None:
+        """Change the time."""
+        self._values["native_value"] = value
+
+
+def init(empty=False):
+    """Initialize the platform with entities."""
+    global ENTITIES
+
+    ENTITIES = (
+        []
+        if empty
+        else [
+            MockDateTimeEntity(
+                name="test",
+                unique_id=UNIQUE_DATETIME,
+                native_value=datetime(2020, 1, 1, 1, 2, 3, tzinfo=timezone.utc),
+            ),
+        ]
+    )
+
+
+async def async_setup_platform(
+    hass, config, async_add_entities_callback, discovery_info=None
+):
+    """Return mock entities."""
+    async_add_entities_callback(ENTITIES)