diff --git a/rhodecode/tests/lib/test_jsonalchemy.py b/rhodecode/tests/lib/test_jsonalchemy.py
--- a/rhodecode/tests/lib/test_jsonalchemy.py
+++ b/rhodecode/tests/lib/test_jsonalchemy.py
@@ -21,7 +21,22 @@
 import pickle
 import pytest
 
-from rhodecode.lib.jsonalchemy import MutationDict, MutationList
+from sqlalchemy import Column, String, create_engine
+from sqlalchemy.orm import sessionmaker
+from sqlalchemy.ext.declarative import declarative_base
+
+from rhodecode.lib.jsonalchemy import (
+    MutationDict, MutationList, MutationObj, JsonType)
+
+
+@pytest.fixture
+def engine():
+    return create_engine('sqlite://')
+
+
+@pytest.fixture
+def session(engine):
+    return sessionmaker(bind=engine)()
 
 
 def test_mutation_dict_is_picklable():
@@ -30,12 +45,14 @@ def test_mutation_dict_is_picklable():
     loaded = pickle.loads(dumped)
     assert loaded == mutation_dict
 
+
 def test_mutation_list_is_picklable():
     mutation_list = MutationList(['a', 'b', 'c'])
     dumped = pickle.dumps(mutation_list)
     loaded = pickle.loads(dumped)
     assert loaded == mutation_list
 
+
 def test_mutation_dict_with_lists_is_picklable():
     mutation_dict = MutationDict({
         'key': MutationList(['values', MutationDict({'key': 'value'})])
@@ -43,3 +60,48 @@ def test_mutation_dict_with_lists_is_pic
     dumped = pickle.dumps(mutation_dict)
     loaded = pickle.loads(dumped)
     assert loaded == mutation_dict
+
+
+def test_mutation_types_with_nullable(engine, session):
+    # TODO: dan: ideally want to make this parametrized python => sql tests eg:
+    # (MutationObj, 5) => '5'
+    # (MutationObj, {'a': 5}) => '{"a": 5}'
+    # (MutationObj, None) => 'null' <- think about if None is 'null' or NULL
+
+    Base = declarative_base()
+
+    class DummyModel(Base):
+        __tablename__ = 'some_table'
+        name = Column(String, primary_key=True)
+        json_list = Column(MutationList.as_mutable(JsonType('list')))
+        json_dict = Column(MutationDict.as_mutable(JsonType('dict')))
+        json_obj = Column(MutationObj.as_mutable(JsonType()))
+
+    Base.metadata.create_all(engine)
+
+    obj_nulls = DummyModel(name='nulls')
+    obj_stuff = DummyModel(
+        name='stuff', json_list=[1,2,3], json_dict={'a': 5}, json_obj=9)
+
+    session.add(obj_nulls)
+    session.add(obj_stuff)
+    session.commit()
+    session.expire_all()
+
+    assert engine.execute(
+        "select * from some_table where name = 'nulls';").first() == (
+        (u'nulls', None, None, None)
+    )
+    ret_nulls = session.query(DummyModel).get('nulls')
+    assert ret_nulls.json_list == []
+    assert ret_nulls.json_dict == {}
+    assert ret_nulls.json_obj is None
+
+    assert engine.execute(
+        "select * from some_table where name = 'stuff';").first() == (
+        (u'stuff', u'[1, 2, 3]', u'{"a": 5}', u'9')
+    )
+    ret_stuff = session.query(DummyModel).get('stuff')
+    assert ret_stuff.json_list == [1, 2, 3]
+    assert ret_stuff.json_dict == {'a': 5}
+    assert ret_stuff.json_obj == 9