diff --git a/tests/base.py b/tests/base.py
index 2879a85..4558cc2 100644
--- a/tests/base.py
+++ b/tests/base.py
@@ -28,10 +28,13 @@ class LunchoTests(unittest.TestCase):
     #  Common assertions for lunch-o
     # ------------------------------------------------------------
 
-    def assertJson(self, expected, response):
-        """Compare JSONs."""
-        if not isinstance(response, dict):
-            response = json.loads(response)
+    def assertJson(self, response, expected):
+        """Compare JSONs.
+
+        :param response: a test_client response
+        :param expected: expected response
+        :type expected: dict"""
+        response = json.loads(response.data)
 
         for key in expected:
             if not key in response:
diff --git a/tests/group_tests.py b/tests/group_tests.py
index 3f0399b..68778fd 100644
--- a/tests/group_tests.py
+++ b/tests/group_tests.py
@@ -32,7 +32,7 @@ class TestGroups(LunchoTests):
         expected = {'status': 'OK',
                     'groups': []}
         self.assertStatusCode(rv, 200)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_create_group(self):
         """Test creating a group."""
@@ -43,7 +43,7 @@ class TestGroups(LunchoTests):
         expected = {'status': 'OK', 'id': 1}    # always 1 'cause the database
                                                 # is erased on every test
         self.assertStatusCode(rv, 200)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_create_group_unverified_account(self):
         """Try creating a group with an account that's not verified yet."""
@@ -57,7 +57,7 @@ class TestGroups(LunchoTests):
         expected = {'status': 'ERROR',
                     'error': 'Account not verified'}
         self.assertStatusCode(rv, 412)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_user_in_own_group(self):
         """The user must belong to a group it owns."""
@@ -69,7 +69,7 @@ class TestGroups(LunchoTests):
                                 'name': 'Test group',
                                 'admin': True}]}
         self.assertStatusCode(rv, 200)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
 
 class TestExistingGroups(LunchoTests):
@@ -102,7 +102,7 @@ class TestExistingGroups(LunchoTests):
                        request)
         expected = {'status': 'OK'}
         self.assertStatusCode(rv, 200)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
         # check the database
         group = Group.query.get(groupId)
@@ -126,7 +126,7 @@ class TestExistingGroups(LunchoTests):
             request)
         expected = {'status': 'OK'}
         self.assertStatusCode(rv, 200)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
         # check the database
         group = Group.query.get(groupId)
@@ -142,7 +142,7 @@ class TestExistingGroups(LunchoTests):
             request)
         expected = {'status': 'ERROR', 'error': 'Group not found'}
         self.assertStatusCode(rv, 404)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_delete_group(self):
         """Delete a group."""
@@ -152,7 +152,7 @@ class TestExistingGroups(LunchoTests):
             groupId=groupId))
         expected = {'status': 'OK'}
         self.assertStatusCode(rv, 200)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_delete_unknown_group(self):
         """Delete a group that doesn't exist."""
@@ -162,7 +162,7 @@ class TestExistingGroups(LunchoTests):
             groupId=groupId))
         expected = {'status': 'ERROR', 'error': 'Group not found'}
         self.assertStatusCode(rv, 404)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_delete_not_admin(self):
         """Try to delete a group when the user is not the admin."""
@@ -178,7 +178,7 @@ class TestExistingGroups(LunchoTests):
             groupId=self.group.id))
         expected = {'status': 'ERROR', 'error': 'User is not admin'}
         self.assertStatusCode(rv, 401)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/tests/users_tests.py b/tests/users_tests.py
index 0ac0cf1..7696a1a 100644
--- a/tests/users_tests.py
+++ b/tests/users_tests.py
@@ -22,7 +22,7 @@ class TestUsers(LunchoTests):
         rv = self.put('/user/', request)
 
         self.assertStatusCode(rv, 200)
-        self.assertJson({'status': 'OK'}, rv.data)
+        self.assertJson(rv, {'status': 'OK'})
 
         # db check
         self.assertIsNotNone(User.query.filter_by(username='username').first())
@@ -40,7 +40,7 @@ class TestUsers(LunchoTests):
         expected = {"status": "ERROR",
                     "error": "Username already exists"}
         self.assertStatusCode(rv, 409)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_no_json(self):
         """Do a request that it's not JSON."""
@@ -49,7 +49,7 @@ class TestUsers(LunchoTests):
         expected = {"error": "Request MUST be in JSON format",
                     "status": "ERROR"}
         self.assertStatusCode(rv, 400)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_missing_fields(self):
         """Send a request with missing fields."""
@@ -59,7 +59,7 @@ class TestUsers(LunchoTests):
         expected = {'error': 'Missing fields: username, full_name',
                     'status': 'ERROR'}
         self.assertStatusCode(rv, 400)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
 
 class TestExistingUsers(LunchoTests):
@@ -85,7 +85,7 @@ class TestExistingUsers(LunchoTests):
 
         expected = {'status': 'OK'}
         self.assertStatusCode(rv, 200)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
         # check in the database
         user = User.query.filter_by(username='test').first()
@@ -102,7 +102,7 @@ class TestExistingUsers(LunchoTests):
         expected = {'status': 'ERROR',
                     'error': 'User not found (via token)'}
         self.assertStatusCode(rv, 404)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_expired_token(self):
         """Send a token that exists but it's not valid for today."""
@@ -119,7 +119,7 @@ class TestExistingUsers(LunchoTests):
         expected = {'status': 'ERROR',
                     'error': 'Invalid token'}
         self.assertStatusCode(rv, 400)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_delete_user(self):
         """Delete a user."""
@@ -127,7 +127,7 @@ class TestExistingUsers(LunchoTests):
 
         expected = {'status': 'OK'}
         self.assertStatusCode(rv, 200)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
         # check the database
         user = User.query.filter_by(username='test').first()
@@ -140,7 +140,7 @@ class TestExistingUsers(LunchoTests):
         expected = {'status': 'ERROR',
                     'error': 'User not found (via token)'}
         self.assertStatusCode(rv, 404)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
     def test_delete_expired_token(self):
         """Send a delete to a token for yesterday."""
@@ -153,7 +153,7 @@ class TestExistingUsers(LunchoTests):
         expected = {'status': 'ERROR',
                     'error': 'Invalid token'}
         self.assertStatusCode(rv, 400)
-        self.assertJson(expected, rv.data)
+        self.assertJson(rv, expected)
 
 
 if __name__ == '__main__':