diff --git a/tests/test_registry.py b/tests/test_registry.py
index b9d39e7ce..3f4f143e6 100644
--- a/tests/test_registry.py
+++ b/tests/test_registry.py
@@ -13,8 +13,59 @@ class MySchema(Schema):
     class MySubSchema(Schema):
         pass
 
+    # by classname
     assert 'MySchema' in class_registry._registry
     assert 'MySubSchema' in class_registry._registry
+    # by fullpath
+    assert 'tests.test_registry.MySchema' in class_registry._registry
+    assert 'tests.test_registry.MySubSchema' in class_registry._registry
+
+
+def test_serializer_class_registry_register_same_classname_different_module():
+
+    reglen = len(class_registry._registry)
+
+    cls1 = type('MyTestRegSchema', (Schema,), {'__module__': 'modA'})
+
+    assert 'MyTestRegSchema' in class_registry._registry
+    assert len(class_registry._registry.get('MyTestRegSchema')) == 1
+    assert 'modA.MyTestRegSchema' in class_registry._registry
+    #  storing for classname and fullpath
+    assert len(class_registry._registry) == reglen + 2
+
+    cls2 = type('MyTestRegSchema', (Schema,), {'__module__': 'modB'})
+
+    assert 'MyTestRegSchema' in class_registry._registry
+    #  aggregating classes with same name from different modules
+    assert len(class_registry._registry.get('MyTestRegSchema')) == 2
+    assert 'modB.MyTestRegSchema' in class_registry._registry
+    #  storing for same classname (+0) and different module (+1)
+    assert len(class_registry._registry) == reglen + 2 + 1
+
+
+def test_serializer_class_registry_override_if_same_classname_same_module():
+
+    reglen = len(class_registry._registry)
+
+    cls1 = type('MyTestReg2Schema', (Schema,), {'__module__': 'SameModulePath'})
+
+    assert 'MyTestReg2Schema' in class_registry._registry
+    assert len(class_registry._registry.get('MyTestReg2Schema')) == 1
+    assert 'SameModulePath.MyTestReg2Schema' in class_registry._registry
+    assert len(class_registry._registry.get('SameModulePath.MyTestReg2Schema')) == 1
+    #  storing for classname and fullpath
+    assert len(class_registry._registry) == reglen + 2
+
+    cls2 = type('MyTestReg2Schema', (Schema,), {'__module__': 'SameModulePath'})
+
+    assert 'MyTestReg2Schema' in class_registry._registry
+    #  overriding same class name and same module
+    assert len(class_registry._registry.get('MyTestReg2Schema')) == 1
+    assert 'SameModulePath.MyTestReg2Schema' in class_registry._registry
+    #  overriding same fullpath
+    assert len(class_registry._registry.get('SameModulePath.MyTestReg2Schema')) == 1
+    #  overriding for same classname (+0) and different module (+0)
+    assert len(class_registry._registry) == reglen + 2
 
 
 class A: