test(webui): add unit tests for ConfigSchemaGenerator

- Test field descriptions from field_docs
- Test json_schema_extra merging
- Test Pydantic constraints mapping
- Test nested model schema handling
- Test fields without extra metadata

All 5 tests passing. Completes Task 7 of webui-config-visualization-refactor plan.

pytests/conftest.py

@@ -0,0 +1,6 @@
+import sys
+from pathlib import Path
+
+# Add project root to Python path so src imports work
+project_root = Path(__file__).parent.parent.absolute()
+sys.path.insert(0, str(project_root))

pytests/webui/test_config_schema.py

@@ -0,0 +1,78 @@
+import pytest
+
+from src.config.official_configs import ChatConfig
+from src.config.config import Config
+from src.webui.config_schema import ConfigSchemaGenerator
+
+
+def test_field_docs_in_schema():
+    """Test that field descriptions are correctly extracted from field_docs (docstrings)."""
+    schema = ConfigSchemaGenerator.generate_schema(ChatConfig)
+    talk_value = next(f for f in schema["fields"] if f["name"] == "talk_value")
+
+    # Verify description field exists
+    assert "description" in talk_value
+    # Verify description contains expected Chinese text from the docstring
+    assert "聊天频率" in talk_value["description"]
+
+
+def test_json_schema_extra_merged():
+    """Test that json_schema_extra fields are correctly merged into output."""
+    schema = ConfigSchemaGenerator.generate_schema(ChatConfig)
+    talk_value = next(f for f in schema["fields"] if f["name"] == "talk_value")
+
+    # Verify UI metadata fields from json_schema_extra exist
+    assert talk_value.get("x-widget") == "slider"
+    assert talk_value.get("x-icon") == "message-circle"
+    assert talk_value.get("step") == 0.1
+
+
+def test_pydantic_constraints_mapped():
+    """Test that Pydantic constraints (ge/le) are correctly mapped to minValue/maxValue."""
+    schema = ConfigSchemaGenerator.generate_schema(ChatConfig)
+    talk_value = next(f for f in schema["fields"] if f["name"] == "talk_value")
+
+    # Verify constraints are mapped to frontend naming convention
+    assert "minValue" in talk_value
+    assert "maxValue" in talk_value
+    assert talk_value["minValue"] == 0  # From ge=0
+    assert talk_value["maxValue"] == 1  # From le=1
+
+
+def test_nested_model_schema():
+    """Test that nested models (ConfigBase fields) are correctly handled."""
+    schema = ConfigSchemaGenerator.generate_schema(Config)
+
+    # Verify nested structure exists
+    assert "nested" in schema
+    assert "chat" in schema["nested"]
+
+    # Verify nested chat schema is complete
+    chat_schema = schema["nested"]["chat"]
+    assert chat_schema["className"] == "ChatConfig"
+    assert "fields" in chat_schema
+
+    # Verify nested schema fields include description and metadata
+    talk_value = next(f for f in chat_schema["fields"] if f["name"] == "talk_value")
+    assert "description" in talk_value
+    assert talk_value.get("x-widget") == "slider"
+    assert talk_value.get("minValue") == 0
+
+
+def test_field_without_extra_metadata():
+    """Test that fields without json_schema_extra still generate valid schema."""
+    schema = ConfigSchemaGenerator.generate_schema(ChatConfig)
+    max_context_size = next(f for f in schema["fields"] if f["name"] == "max_context_size")
+
+    # Verify basic fields are generated
+    assert "name" in max_context_size
+    assert max_context_size["name"] == "max_context_size"
+    assert "type" in max_context_size
+    assert max_context_size["type"] == "integer"
+    assert "label" in max_context_size
+    assert "required" in max_context_size
+
+    # Verify no x-widget or x-icon from json_schema_extra (since field has none)
+    # These fields should only be present if explicitly defined in json_schema_extra
+    assert not max_context_size.get("x-widget")
+    assert not max_context_size.get("x-icon")