Added failing test for relay mutation

graphene/relay/tests/test_mutation.py

@@ -6,6 +6,10 @@ from ...types.scalars import String
 from ..mutation import ClientIDMutation
 
 
+class SharedFields(object):
+    shared = String()
+
+
 class SaySomething(ClientIDMutation):
 
     class Input:
@@ -18,12 +22,24 @@ class SaySomething(ClientIDMutation):
         return SaySomething(phrase=str(what))
 
 
+class OtherMutation(ClientIDMutation):
+
+    class Input(SharedFields):
+        additional_field = String()
+
+    @classmethod
+    def mutate_and_get_payload(cls, args, context, info):
+        what = args.get('what')
+        return SaySomething(shared=str(what), additional_field='additional')
+
+
 class RootQuery(ObjectType):
     something = String()
 
 
 class Mutation(ObjectType):
     say = SaySomething.Field()
+    other = OtherMutation.Field()
 
 schema = Schema(query=RootQuery, mutation=Mutation)
 
@@ -59,6 +75,19 @@ def test_mutation_input():
     assert fields['client_mutation_id'].type == String
 
 
+def test_subclassed_mutation_input():
+    Input = OtherMutation.Input
+    assert issubclass(Input, InputObjectType)
+    fields = Input._meta.fields
+    assert list(fields.keys()) == ['shared', 'additional_field', 'client_mutation_id']
+    assert isinstance(fields['shared'], InputField)
+    assert fields['shared'].type == String
+    assert isinstance(fields['additional_field'], InputField)
+    assert fields['additional_field'].type == String
+    assert isinstance(fields['client_mutation_id'], InputField)
+    assert fields['client_mutation_id'].type == String
+
+
 # def test_node_query():
 #     executed = schema.execute(
 #         'mutation a { say(input: {what:"hello", clientMutationId:"1"}) { phrase } }'