De-duplicate MQTT config_flow code (#79369)

* De-duplicate config_flow code

* De duplicate code birth and will

tests/components/mqtt/test_config_flow.py

@@ -188,15 +188,12 @@ async def test_manual_config_set(
     # Check we tried the connection, with precedence for config entry settings
     mock_try_connection.assert_called_once_with(
         {
-            "broker": "bla",
+            "broker": "127.0.0.1",
+            "protocol": "3.1.1",
             "keepalive": 60,
             "discovery_prefix": "homeassistant",
-            "protocol": "3.1.1",
+            "port": 1883,
         },
-        "127.0.0.1",
-        1883,
-        None,
-        None,
     )
     # Check config entry got setup
     assert len(mock_finish_setup.mock_calls) == 1
@@ -291,6 +288,44 @@ async def test_hassio_confirm(hass, mock_try_connection_success, mock_finish_set
     assert len(mock_finish_setup.mock_calls) == 1
 
 
+async def test_hassio_cannot_connect(
+    hass, mock_try_connection_time_out, mock_finish_setup
+):
+    """Test a config flow is aborted when a connection was not successful."""
+    mock_try_connection.return_value = True
+
+    result = await hass.config_entries.flow.async_init(
+        "mqtt",
+        data=HassioServiceInfo(
+            config={
+                "addon": "Mock Addon",
+                "host": "mock-broker",
+                "port": 1883,
+                "username": "mock-user",
+                "password": "mock-pass",
+                "protocol": "3.1.1",  # Set by the addon's discovery, ignored by HA
+                "ssl": False,  # Set by the addon's discovery, ignored by HA
+            }
+        ),
+        context={"source": config_entries.SOURCE_HASSIO},
+    )
+    assert result["type"] == "form"
+    assert result["step_id"] == "hassio_confirm"
+    assert result["description_placeholders"] == {"addon": "Mock Addon"}
+
+    mock_try_connection_time_out.reset_mock()
+    result = await hass.config_entries.flow.async_configure(
+        result["flow_id"], {"discovery": True}
+    )
+
+    assert result["type"] == "form"
+    assert result["errors"]["base"] == "cannot_connect"
+    # Check we tried the connection
+    assert len(mock_try_connection_time_out.mock_calls)
+    # Check config entry got setup
+    assert len(mock_finish_setup.mock_calls) == 0
+
+
 @patch(
     "homeassistant.config.async_hass_config_yaml",
     AsyncMock(return_value={}),
@@ -299,7 +334,7 @@ async def test_option_flow(
     hass,
     mqtt_mock_entry_no_yaml_config,
     mock_try_connection,
-    mock_reload_after_entry_update,
+    caplog,
 ):
     """Test config flow options."""
     mqtt_mock = await mqtt_mock_entry_no_yaml_config()
@@ -372,7 +407,10 @@ async def test_option_flow(
     await hass.async_block_till_done()
     assert config_entry.title == "another-broker"
     # assert that the entry was reloaded with the new config
-    assert mock_reload_after_entry_update.call_count == 1
+    assert (
+        "<Event call_service[L]: domain=mqtt, service=reload, service_data=>"
+        in caplog.text
+    )
 
 
 async def test_disable_birth_will(