Allow undefined schema type

openapi_core/schemas.py

@@ -36,10 +36,10 @@ class Schema(object):
     """Represents an OpenAPI Schema."""
 
     def __init__(
-            self, schema_type, model=None, properties=None, items=None,
+            self, schema_type=None, model=None, properties=None, items=None,
             schema_format=None, required=None, default=None, nullable=False,
             enum=None, deprecated=False, all_of=None):
-        self.type = SchemaType(schema_type)
+        self.type = schema_type and SchemaType(schema_type)
         self.model = model
         self.properties = properties and dict(properties) or {}
         self.items = items
@@ -76,12 +76,12 @@ def cast(self, value):
         """Cast value to schema type"""
         if value is None:
             if not self.nullable:
-                raise InvalidValueType(
-                    "Failed to cast value of {0} to {1}".format(
-                        value, self.type)
-                )
+                raise InvalidValueType("Null value for non-nullable schema")
             return self.default
 
+        if self.type is None:
+            return value
+
         cast_mapping = self.get_cast_mapping()
 
         if self.type in cast_mapping and value == '':
@@ -167,7 +167,7 @@ def __init__(self, dereferencer):
     def create(self, schema_spec):
         schema_deref = self.dereferencer.dereference(schema_spec)
 
-        schema_type = schema_deref['type']
+        schema_type = schema_deref.get('type')
         schema_format = schema_deref.get('format')
         model = schema_deref.get('x-model', None)
         required = schema_deref.get('required', False)
@@ -192,9 +192,10 @@ def create(self, schema_spec):
             items = self._create_items(items_spec)
 
         return Schema(
-            schema_type, model=model, properties=properties, items=items,
-            schema_format=schema_format, required=required, default=default,
-            nullable=nullable, enum=enum, deprecated=deprecated, all_of=all_of,
+            schema_type=schema_type, model=model, properties=properties,
+            items=items, schema_format=schema_format, required=required,
+            default=default, nullable=nullable, enum=enum,
+            deprecated=deprecated, all_of=all_of,
         )
 
     @property

tests/integration/data/v3.0/petstore.yaml

@@ -84,11 +84,7 @@ paths:
         '201':
           description: Null response
         default:
-          description: unexpected error
-          content:
-            application/json:
-              schema:
-                $ref: "#/components/schemas/Error"
+          $ref: "#/components/responses/ErrorResponse"
   /pets/{petId}:
     get:
       summary: Info for a specific pet
@@ -192,10 +188,19 @@ components:
           format: int32
         message:
           type: string
+    ExtendedError:
+      allOf:
+        - $ref: "#/components/schemas/Error"
+        - type: object
+          required:
+            - rootCause
+          properties:
+            rootCause:
+              type: string
   responses:
       ErrorResponse:
         description: unexpected error
         content:
           application/json:
             schema:
-              $ref: "#/components/schemas/Error"
+              $ref: "#/components/schemas/ExtendedError"

tests/integration/test_petstore.py

@@ -619,3 +619,39 @@ def test_get_pet(self, spec, response_validator):
 
         assert response_result.errors == []
         assert response_result.data == data_json
+
+    def test_get_pet_not_found(self, spec, response_validator):
+        host_url = 'http://petstore.swagger.io/v1'
+        path_pattern = '/v1/pets/{petId}'
+        view_args = {
+            'petId': '1',
+        }
+        request = MockRequest(
+            host_url, 'GET', '/pets/1',
+            path_pattern=path_pattern, view_args=view_args,
+        )
+
+        parameters = request.get_parameters(spec)
+
+        assert parameters == {
+            'path': {
+                'petId': 1,
+            }
+        }
+
+        body = request.get_body(spec)
+
+        assert body is None
+
+        data_json = {
+            'code': 404,
+            'message': 'Not found',
+            'rootCause': 'Pet not found',
+        }
+        data = json.dumps(data_json)
+        response = MockResponse(data, status_code=404)
+
+        response_result = response_validator.validate(request, response)
+
+        assert response_result.errors == []
+        assert response_result.data == data