Fix preview during option flow

homeassistant/components/min_max/config_flow.py

@@ -74,16 +74,17 @@ class ConfigFlowHandler(SchemaConfigFlowHandler, domain=DOMAIN):
     config_flow = CONFIG_FLOW
     options_flow = OPTIONS_FLOW
 
-    def __init__(self) -> None:
-        """Initialize config flow."""
-        super().__init__()
-        hass = async_get_hass()
-        websocket_api.async_register_command(hass, ws_preview_min_max)
-
     def async_config_entry_title(self, options: Mapping[str, Any]) -> str:
         """Return config entry title."""
         return cast(str, options["name"]) if "name" in options else ""
 
+    @callback
+    @staticmethod
+    def async_setup_preview() -> None:
+        """Set up preview WS API."""
+        hass = async_get_hass()
+        websocket_api.async_register_command(hass, ws_preview_min_max)
+
 
 @callback
 @websocket_api.websocket_command(

homeassistant/helpers/schema_config_entry_flow.py

@@ -274,6 +274,8 @@ class SchemaConfigFlowHandler(config_entries.ConfigFlow, ABC):
             if cls.options_flow is None:
                 raise UnknownHandler
 
+            cls.async_setup_preview()
+
             return SchemaOptionsFlowHandler(
                 config_entry, cls.options_flow, cls.async_options_flow_finished
             )
@@ -288,6 +290,12 @@ class SchemaConfigFlowHandler(config_entries.ConfigFlow, ABC):
     def __init__(self) -> None:
         """Initialize config flow."""
         self._common_handler = SchemaCommonFlowHandler(self, self.config_flow, None)
+        self.async_setup_preview()
+
+    @callback
+    @staticmethod
+    def async_setup_preview() -> None:
+        """Set up preview."""
 
     @classmethod
     @callback

tests/components/min_max/test_config_flow.py

@@ -199,3 +199,59 @@ async def test_config_flow_preview(hass: HomeAssistant, hass_ws_client) -> None:
         },
         "state": "20.0",
     }
+
+
+async def test_option_flow_preview(hass: HomeAssistant, hass_ws_client) -> None:
+    """Test the option flow preview."""
+    client = await hass_ws_client(hass)
+
+    # Setup the config entry
+    config_entry = MockConfigEntry(
+        data={},
+        domain=DOMAIN,
+        options={
+            "entity_ids": ["sensor.input_one", "sensor.input_two"],
+            "name": "My min_max",
+            "round_digits": 0,
+            "type": "min",
+        },
+        title="My min_max",
+    )
+    config_entry.add_to_hass(hass)
+    assert await hass.config_entries.async_setup(config_entry.entry_id)
+    await hass.async_block_till_done()
+
+    input_sensors = ["sensor.input_one", "sensor.input_two"]
+
+    result = await hass.config_entries.options.async_init(config_entry.entry_id)
+    assert result["type"] == FlowResultType.FORM
+    assert result["errors"] is None
+    assert result["preview"] == "min_max_preview"
+
+    hass.states.async_set("sensor.input_one", "10")
+    hass.states.async_set("sensor.input_two", "20")
+
+    await client.send_json(
+        {
+            "id": 1,
+            "type": "min_max/preview",
+            "flow_id": "blah",
+            "flow_type": "config_flow",
+            "user_input": {
+                "name": "My min_max",
+                "entity_ids": input_sensors,
+                "type": "min",
+            },
+        }
+    )
+    msg = await client.receive_json()
+    assert msg["success"]
+    assert msg["result"] == {
+        "attributes": {
+            "friendly_name": "My min_max",
+            "icon": "mdi:calculator",
+            "min_entity_id": "sensor.input_one",
+            "state_class": "measurement",
+        },
+        "state": "10.0",
+    }