Ensure a state change tracker setup from inside a state change listener does not fire immediately (#37924)

Co-authored-by: Paulus Schoutsen <paulus@home-assistant.io>

tests/helpers/test_event.py

@@ -1011,3 +1011,104 @@ async def test_async_call_later(hass):
     assert p_action is action
     assert p_point == now + timedelta(seconds=3)
     assert remove is mock()
+
+
+async def test_track_state_change_event_chain_multple_entity(hass):
+    """Test that adding a new state tracker inside a tracker does not fire right away."""
+    tracker_called = []
+    chained_tracker_called = []
+
+    chained_tracker_unsub = []
+    tracker_unsub = []
+
+    @ha.callback
+    def chained_single_run_callback(event):
+        old_state = event.data.get("old_state")
+        new_state = event.data.get("new_state")
+
+        chained_tracker_called.append((old_state, new_state))
+
+    @ha.callback
+    def single_run_callback(event):
+        old_state = event.data.get("old_state")
+        new_state = event.data.get("new_state")
+
+        tracker_called.append((old_state, new_state))
+
+        chained_tracker_unsub.append(
+            async_track_state_change_event(
+                hass, ["light.bowl", "light.top"], chained_single_run_callback
+            )
+        )
+
+    tracker_unsub.append(
+        async_track_state_change_event(
+            hass, ["light.bowl", "light.top"], single_run_callback
+        )
+    )
+
+    hass.states.async_set("light.bowl", "on")
+    hass.states.async_set("light.top", "on")
+    await hass.async_block_till_done()
+
+    assert len(tracker_called) == 2
+    assert len(chained_tracker_called) == 1
+    assert len(tracker_unsub) == 1
+    assert len(chained_tracker_unsub) == 2
+
+    hass.states.async_set("light.bowl", "off")
+    await hass.async_block_till_done()
+
+    assert len(tracker_called) == 3
+    assert len(chained_tracker_called) == 3
+    assert len(tracker_unsub) == 1
+    assert len(chained_tracker_unsub) == 3
+
+
+async def test_track_state_change_event_chain_single_entity(hass):
+    """Test that adding a new state tracker inside a tracker does not fire right away."""
+    tracker_called = []
+    chained_tracker_called = []
+
+    chained_tracker_unsub = []
+    tracker_unsub = []
+
+    @ha.callback
+    def chained_single_run_callback(event):
+        old_state = event.data.get("old_state")
+        new_state = event.data.get("new_state")
+
+        chained_tracker_called.append((old_state, new_state))
+
+    @ha.callback
+    def single_run_callback(event):
+        old_state = event.data.get("old_state")
+        new_state = event.data.get("new_state")
+
+        tracker_called.append((old_state, new_state))
+
+        chained_tracker_unsub.append(
+            async_track_state_change_event(
+                hass, "light.bowl", chained_single_run_callback
+            )
+        )
+
+    tracker_unsub.append(
+        async_track_state_change_event(hass, "light.bowl", single_run_callback)
+    )
+
+    hass.states.async_set("light.bowl", "on")
+    await hass.async_block_till_done()
+
+    assert len(tracker_called) == 1
+    assert len(chained_tracker_called) == 0
+    assert len(tracker_unsub) == 1
+    assert len(chained_tracker_unsub) == 1
+
+    hass.states.async_set("light.bowl", "off")
+    await hass.async_block_till_done()
+
+    assert len(tracker_called) == 2
+    assert len(chained_tracker_called) == 1
+    assert len(tracker_unsub) == 1
+    assert len(chained_tracker_unsub) == 2