Ensure selected entity is pre-selected in homekit options flow (#63628)

* Ensure selected entity is pre-selected in homekit options flow

- We recently adjusted the flow to exclude entities that had
  been deleted from breaking the UI validation. We need to include
  single entities in the set of all supported entities since
  accessory mode has no domain filter

* tweak

* Additional fixes

* small tweak to speed up building the set

* merged fixed version for test branch

tests/components/homekit/test_config_flow.py

@@ -7,6 +7,8 @@ from homeassistant.config_entries import SOURCE_IGNORE, SOURCE_IMPORT
 from homeassistant.const import CONF_NAME, CONF_PORT
 from homeassistant.setup import async_setup_component
 
+from .util import PATH_HOMEKIT, async_init_entry
+
 from tests.common import MockConfigEntry
 
 
@@ -1065,11 +1067,13 @@ async def test_options_flow_blocked_when_from_yaml(hass, mock_get_source_ip):
         assert result2["type"] == data_entry_flow.RESULT_TYPE_CREATE_ENTRY
 
 
-async def test_options_flow_include_mode_basic_accessory(hass, mock_get_source_ip):
+@patch(f"{PATH_HOMEKIT}.async_port_is_available", return_value=True)
+async def test_options_flow_include_mode_basic_accessory(
+    port_mock, hass, mock_get_source_ip, hk_driver, mock_async_zeroconf
+):
     """Test config flow options in include mode with a single accessory."""
-
     config_entry = _mock_config_entry_with_options_populated()
-    config_entry.add_to_hass(hass)
+    await async_init_entry(hass, config_entry)
 
     hass.states.async_set("media_player.tv", "off")
     hass.states.async_set("media_player.sonos", "off")
@@ -1101,7 +1105,48 @@ async def test_options_flow_include_mode_basic_accessory(hass, mock_get_source_i
 
     assert result2["type"] == data_entry_flow.RESULT_TYPE_FORM
     assert result2["step_id"] == "include_exclude"
-    assert _get_schema_default(result2["data_schema"].schema, "entities") == []
+    assert _get_schema_default(result2["data_schema"].schema, "entities") is None
+
+    result3 = await hass.config_entries.options.async_configure(
+        result2["flow_id"],
+        user_input={"entities": "media_player.tv"},
+    )
+    assert result3["type"] == data_entry_flow.RESULT_TYPE_CREATE_ENTRY
+    assert config_entry.options == {
+        "mode": "accessory",
+        "filter": {
+            "exclude_domains": [],
+            "exclude_entities": [],
+            "include_domains": [],
+            "include_entities": ["media_player.tv"],
+        },
+    }
+
+    # Now we check again to make sure the single entity is still
+    # preselected
+
+    result = await hass.config_entries.options.async_init(
+        config_entry.entry_id, context={"show_advanced_options": False}
+    )
+
+    assert result["type"] == data_entry_flow.RESULT_TYPE_FORM
+    assert result["step_id"] == "init"
+    assert result["data_schema"]({}) == {
+        "domains": ["media_player"],
+        "mode": "accessory",
+    }
+
+    result2 = await hass.config_entries.options.async_configure(
+        result["flow_id"],
+        user_input={"domains": ["media_player"], "mode": "accessory"},
+    )
+
+    assert result2["type"] == data_entry_flow.RESULT_TYPE_FORM
+    assert result2["step_id"] == "include_exclude"
+    assert (
+        _get_schema_default(result2["data_schema"].schema, "entities")
+        == "media_player.tv"
+    )
 
     result3 = await hass.config_entries.options.async_configure(
         result2["flow_id"],