chore: Convert all FailureContext class attributes to instance attr…

…ibutes

For simpler serialization via `attrs`

docs/changelog.rst

@@ -9,6 +9,7 @@ Changelog
 - ``ExecutionEvent.asdict`` adds the ``event_type`` field which is the event class name.
 - Add API schema to the ``Initialized`` event.
 - **Internal**: Add ``SerializedCase.cookies``
+- Convert all ``FailureContext`` class attributes to instance attributes. For simpler serialization via ``attrs``.
 
 `3.9.0`_ - 2021-06-07
 ---------------------

src/schemathesis/failures.py

@@ -11,81 +11,89 @@ class FailureContext:
     title: str
     # A longer one
     message: str
+    type: str
 
 
 @attr.s(slots=True, repr=False)
 class ValidationErrorContext(FailureContext):
     """Additional information about JSON Schema validation errors."""
 
-    title = "Non-conforming response payload"
-    message = "Response does not conform to the defined schema"
     validation_message: str = attr.ib()
     schema_path: List[Union[str, int]] = attr.ib()
     schema: Union[Dict[str, Any], bool] = attr.ib()
     instance_path: List[Union[str, int]] = attr.ib()
     instance: Union[None, bool, float, str, list, Dict[str, Any]] = attr.ib()
+    title: str = attr.ib(default="Non-conforming response payload")
+    message: str = attr.ib(default="Response does not conform to the defined schema")
+    type: str = attr.ib(default="json_schema")
 
 
 @attr.s(slots=True, repr=False)
 class JSONDecodeErrorContext(FailureContext):
     """Failed to decode JSON."""
 
-    title = "JSON deserialization error"
-    message = "Response is not a valid JSON"
     validation_message: str = attr.ib()
     document: str = attr.ib()
     position: int = attr.ib()
     lineno: int = attr.ib()
     colno: int = attr.ib()
+    title: str = attr.ib(default="JSON deserialization error")
+    message: str = attr.ib(default="Response is not a valid JSON")
+    type: str = attr.ib(default="json_decode")
 
 
 @attr.s(slots=True, repr=False)
 class ServerError(FailureContext):
-    title = "Internal server error"
-    message = "Server got itself in trouble"
     status_code: int = attr.ib()
+    title: str = attr.ib(default="Internal server error")
+    message: str = attr.ib(default="Server got itself in trouble")
+    type: str = attr.ib(default="server_error")
 
 
 @attr.s(slots=True, repr=False)
 class MissingContentType(FailureContext):
     """Content type header is missing."""
 
-    title = "Missing Content-Type header"
-    message = "Response is missing the `Content-Type` header"
     media_types: List[str] = attr.ib()
+    title: str = attr.ib(default="Missing Content-Type header")
+    message: str = attr.ib(default="Response is missing the `Content-Type` header")
+    type: str = attr.ib(default="missing_content_type")
 
 
 @attr.s(slots=True, repr=False)
 class UndefinedContentType(FailureContext):
     """Response has Content-Type that is not defined in the schema."""
 
-    title = "Undefined Content-Type"
-    message = "Response has `Content-Type` that is not declared in the schema"
     content_type: str = attr.ib()
     defined_content_types: List[str] = attr.ib()
+    title: str = attr.ib(default="Undefined Content-Type")
+    message: str = attr.ib(default="Response has `Content-Type` that is not declared in the schema")
+    type: str = attr.ib(default="undefined_content_type")
 
 
 @attr.s(slots=True, repr=False)
 class UndefinedStatusCode(FailureContext):
     """Response has a status code that is not defined in the schema."""
 
-    title = "Undefined status code"
-    message = "Response has a status code that is not declared in the schema"
     # Response's status code
     status_code: int = attr.ib()
     # Status codes as defined in schema
     defined_status_codes: List[str] = attr.ib()
     # Defined status code with expanded wildcards
     allowed_status_codes: List[int] = attr.ib()
+    title: str = attr.ib(default="Undefined status code")
+    message: str = attr.ib(default="Response has a status code that is not declared in the schema")
+    type: str = attr.ib(default="undefined_status_code")
 
 
 @attr.s(slots=True, repr=False)
 class MissingHeaders(FailureContext):
     """Some required headers are missing."""
 
-    title = "Missing required headers"
-    message = "Response is missing headers required by the schema"
     missing_headers: List[str] = attr.ib()
+    title: str = attr.ib(default="Missing required headers")
+    message: str = attr.ib(default="Response is missing headers required by the schema")
+    type: str = attr.ib(default="missing_headers")
 
 
 @attr.s(slots=True, repr=False)
@@ -95,26 +103,29 @@ class MalformedMediaType(FailureContext):
     Example: `application-json` instead of `application/json`
     """
 
-    title = "Malformed media type name"
-    message = "Media type name is not valid"
     actual: str = attr.ib()
     defined: str = attr.ib()
+    title: str = attr.ib(default="Malformed media type name")
+    message: str = attr.ib(default="Media type name is not valid")
+    type: str = attr.ib(default="malformed_media_type")
 
 
 @attr.s(slots=True, repr=False)
 class ResponseTimeExceeded(FailureContext):
     """Response took longer than expected."""
 
-    title = "Response time exceeded"
-    message = "Response time exceeds the deadline"
     elapsed: float = attr.ib()
     deadline: int = attr.ib()
+    title: str = attr.ib(default="Response time exceeded")
+    message: str = attr.ib(default="Response time exceeds the deadline")
+    type: str = attr.ib(default="response_time_exceeded")
 
 
 @attr.s(slots=True, repr=False)
 class RequestTimeout(FailureContext):
     """Request took longer than timeout."""
 
-    title = "Request timeout"
-    message = "The request timed out"
     timeout: int = attr.ib()
+    title: str = attr.ib(default="Request timeout")
+    message: str = attr.ib(default="The request timed out")
+    type: str = attr.ib(default="request_timeout")