Add a simple test and all of the args.

jsonschema/exceptions.py

@@ -27,10 +27,18 @@ class _Error(Exception):
         schema_path=(),
         parent=None,
     ):
-        # Calling __init__ is important, because otherwise __reduce__ will
+        super(_Error, self).__init__(
-        # return empty args tuple on Py2.7 and unpickling will fail because
+            message,
-        # init requires at least one argument.
+            validator,
-        super(_Error, self).__init__(message)
+            path,
+            cause,
+            context,
+            validator_value,
+            instance,
+            schema,
+            schema_path,
+            parent,
+        )
         self.message = message
         self.path = self.relative_path = deque(path)
         self.schema_path = self.relative_schema_path = deque(schema_path)

jsonschema/tests/test_exceptions.py

@@ -273,7 +273,7 @@ class TestErrorTree(unittest.TestCase):
         self.assertIsInstance(tree["foo"], exceptions.ErrorTree)
 
 
-class TestErrorReprStr(unittest.TestCase):
+class TestErrorInitReprStr(unittest.TestCase):
     def make_error(self, **kwargs):
         defaults = dict(
             message=u"hello",
@@ -295,6 +295,10 @@ class TestErrorReprStr(unittest.TestCase):
         self.assertEqual(message_line, error.message)
         self.assertEqual(rest, expected)
 
+    def test_it_calls_super_and_sets_args(self):
+        error = self.make_error()
+        self.assertGreater(len(error.args), 1)
+
     def test_repr(self):
         self.assertEqual(
             repr(exceptions.ValidationError(message="Hello!")),