Adds __eq__ and test of it

Author: spacether

graphene/types/objecttype.py

@@ -128,6 +128,11 @@ def __init_subclass_with_meta__(
 
     is_type_of = None
 
+    def __eq__(self, other):
+        if isinstance(other, self.__class__):
+            return self.__dict__ == other.__dict__
+        return False
+
     def __init__(self, *args, **kwargs):
         # ObjectType acting as container
         args_len = len(args)

graphene/types/tests/test_objecttype.py

@@ -35,6 +35,40 @@ def get_type(self):
         return MyType
 
 
+def test_equality():
+    # instances of object with no properties are equal
+    class NoPropertiesObject(ObjectType):
+        pass
+
+    my_obj = NoPropertiesObject()
+    assert my_obj == NoPropertiesObject()
+
+
+    # different classes are unequal
+    class OtherNoPropertiesObject(ObjectType):
+        pass
+
+    assert NoPropertiesObject() != OtherNoPropertiesObject()
+
+
+    # compare instances of the same simple class
+    class MyObjectType(ObjectType):
+        prop = String()
+
+    my_obj = MyObjectType(prop="a")
+    assert my_obj == MyObjectType(prop="a")
+    assert my_obj != MyObjectType(prop="b")
+
+
+    # complex instances of the same class
+    # class contains another class in a field
+    class ParentObjectType(ObjectType):
+        child = Field(MyObjectType)
+
+    my_obj = ParentObjectType(child=MyObjectType(prop="a"))
+    assert my_obj == ParentObjectType(child=MyObjectType(prop="a"))
+    assert my_obj != ParentObjectType(child=MyObjectType(prop="b"))
+
 def test_generate_objecttype():
     class MyObjectType(ObjectType):
         """Documentation"""