feature: Properly handle response data validation errors.

Previously validation error on response resulted in 500 Server Error
responses, this commit fixes it and retursn 422 Unprocessable Entity
responses with data similar to Request Validation Error.

Issue: #14

rororo/openapi/exceptions.py

@@ -212,6 +212,20 @@ def from_request_errors(  # type: ignore
             errors=parameters + body,
         )
 
+    @classmethod
+    def from_response_errors(  # type: ignore
+        cls, errors: List[OpenAPIMappingError]
+    ) -> "ValidationError":
+        result = []
+
+        for err in errors:
+            if isinstance(err, OpenAPIMediaTypeError):
+                details = get_media_type_error_details(["response"], err)
+                if details:
+                    result.append(details)
+
+        return cls(message="Response data validation error", errors=result)
+
 
 def ensure_loc(loc: List[PathItem]) -> List[PathItem]:
     return [item for item in loc if item != ""]

rororo/openapi/validators.py

@@ -77,5 +77,7 @@ def validate_response_data(
     validator = ResponseValidator(spec, custom_formatters=CUSTOM_FORMATTERS)
     result = validator.validate(core_request, core_response)
 
-    result.raise_for_errors()
+    if result.errors:
+        raise ValidationError.from_response_errors(result.errors)
+
     return result.data

tests/openapi.json

@@ -126,6 +126,23 @@
         }
       }
     },
+    "/invalid-response": {
+      "get": {
+        "operationId": "retrieve_invalid_response",
+        "responses": {
+          "200": {
+            "description": "Expected response.",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/NestedObject"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
     "/nested-object": {
       "post": {
         "operationId": "retrieve_nested_object_from_request_body",

tests/openapi.yaml

@@ -86,6 +86,17 @@ paths:
         "204":
           description: "Empty response."
 
+  "/invalid-response":
+    get:
+      operationId: "retrieve_invalid_response"
+      responses:
+        "200":
+          description: "Expected response."
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/NestedObject"
+
   "/nested-object":
     post:
       operationId: "retrieve_nested_object_from_request_body"

tests/test_openapi.py

@@ -87,6 +87,11 @@ async def retrieve_empty(request: web.Request) -> web.Response:
     return web.Response(status=204)
 
 
+@operations.register
+async def retrieve_invalid_response(request: web.Request) -> web.Response:
+    return web.json_response({})
+
+
 @operations.register
 async def retrieve_nested_object_from_request_body(
     request: web.Request,
@@ -477,3 +482,46 @@ async def test_validate_empty_response(aiohttp_client, schema_path):
     client = await aiohttp_client(app)
     response = await client.get("/api/empty")
     assert response.status == 204
+
+
+@pytest.mark.parametrize(
+    "schema_path, is_validate_response, expected_status",
+    (
+        (OPENAPI_JSON_PATH, False, 200),
+        (OPENAPI_JSON_PATH, True, 422),
+        (OPENAPI_YAML_PATH, False, 200),
+        (OPENAPI_JSON_PATH, True, 422),
+    ),
+)
+async def test_validate_response(
+    aiohttp_client, schema_path, is_validate_response, expected_status
+):
+    app = setup_openapi(
+        web.Application(),
+        schema_path,
+        operations,
+        server_url="/api",
+        is_validate_response=is_validate_response,
+    )
+
+    client = await aiohttp_client(app)
+    response = await client.get("/api/invalid-response")
+    assert response.status == expected_status
+
+
+@pytest.mark.parametrize("schema_path", (OPENAPI_JSON_PATH, OPENAPI_YAML_PATH))
+async def test_validate_response_error(aiohttp_client, schema_path):
+    app = setup_openapi(
+        web.Application(),
+        schema_path,
+        operations,
+        server_url="/api",
+        is_validate_response=True,
+    )
+
+    client = await aiohttp_client(app)
+    response = await client.get("/api/invalid-response")
+    assert response.status == 422
+    assert await response.json() == {
+        "detail": [{"loc": ["response", "uid"], "message": "Field required"}]
+    }

tests/test_openapi_exceptions.py

@@ -92,19 +92,18 @@ def test_validation_error_from_dict_value_error():
         )
 
 
-def test_validation_error_from_dummy_mapping_error():
-    err = ValidationError.from_request_errors([OpenAPIMappingError()])
-    assert err.errors == []
-    assert err.data is None
-
-
-def test_validation_error_from_dummy_media_type_error():
-    err = ValidationError.from_request_errors([OpenAPIMediaTypeError()])
-    assert err.errors == []
-    assert err.data is None
-
-
-def test_validation_error_from_dummy_operation_error():
-    err = ValidationError.from_request_errors([OpenAPIParameterError()])
+@pytest.mark.parametrize(
+    "method, error",
+    (
+        (ValidationError.from_request_errors, OpenAPIMappingError()),
+        (ValidationError.from_response_errors, OpenAPIMappingError()),
+        (ValidationError.from_request_errors, OpenAPIMediaTypeError()),
+        (ValidationError.from_response_errors, OpenAPIMediaTypeError()),
+        (ValidationError.from_request_errors, OpenAPIParameterError()),
+        (ValidationError.from_response_errors, OpenAPIParameterError()),
+    ),
+)
+def test_validation_error_from_dummy_error(method, error):
+    err = method([error])
     assert err.errors == []
     assert err.data is None