Differentiate between warnings and errors in check_config helper (#102902)

* Differentiate between warnings and errors in check_config helper

* Update tests

* Treat configuration errors in frontend and its dependencies as errors

* Improve test coverage

* Address review comments

* Improve test coverage

* Improve test coverage

* Address review comments

* Add comment

tests/components/config/test_core.py

@@ -1,6 +1,6 @@
 """Test core config."""
 from http import HTTPStatus
-from unittest.mock import patch
+from unittest.mock import Mock, patch
 
 import pytest
 
@@ -37,9 +37,14 @@ async def test_validate_config_ok(
 
     client = await hass_client()
 
+    no_error = Mock()
+    no_error.errors = None
+    no_error.error_str = ""
+    no_error.warning_str = ""
+
     with patch(
-        "homeassistant.components.config.core.async_check_ha_config_file",
-        return_value=None,
+        "homeassistant.components.config.core.check_config.async_check_ha_config_file",
+        return_value=no_error,
     ):
         resp = await client.post("/api/config/core/check_config")
 
@@ -47,10 +52,16 @@ async def test_validate_config_ok(
     result = await resp.json()
     assert result["result"] == "valid"
     assert result["errors"] is None
+    assert result["warnings"] is None
+
+    error_warning = Mock()
+    error_warning.errors = ["beer"]
+    error_warning.error_str = "beer"
+    error_warning.warning_str = "milk"
 
     with patch(
-        "homeassistant.components.config.core.async_check_ha_config_file",
-        return_value="beer",
+        "homeassistant.components.config.core.check_config.async_check_ha_config_file",
+        return_value=error_warning,
     ):
         resp = await client.post("/api/config/core/check_config")
 
@@ -58,6 +69,24 @@ async def test_validate_config_ok(
     result = await resp.json()
     assert result["result"] == "invalid"
     assert result["errors"] == "beer"
+    assert result["warnings"] == "milk"
+
+    warning = Mock()
+    warning.errors = None
+    warning.error_str = ""
+    warning.warning_str = "milk"
+
+    with patch(
+        "homeassistant.components.config.core.check_config.async_check_ha_config_file",
+        return_value=warning,
+    ):
+        resp = await client.post("/api/config/core/check_config")
+
+    assert resp.status == HTTPStatus.OK
+    result = await resp.json()
+    assert result["result"] == "valid"
+    assert result["errors"] is None
+    assert result["warnings"] == "milk"
 
 
 async def test_validate_config_requires_admin(