diff --git a/api/event/serializers.py b/api/event/serializers.py
index 5e01499..44461e6 100644
--- a/api/event/serializers.py
+++ b/api/event/serializers.py
@@ -46,16 +46,17 @@ class EventSpecificSerializerMixin():
 
 # Serializers
 # TODO rajouter des permissions
-class PlaceSerializer(serializers.ModelSerializer,
-                      EventSpecificSerializerMixin):
+class PlaceSerializer(EventSpecificSerializerMixin,
+                      serializers.ModelSerializer):
+
     class Meta:
         model = Place
         fields = ('url', 'id', 'name', 'description', 'event')
 
 
 # TODO rajouter des permissions
-class ActivityTagSerializer(serializers.ModelSerializer,
-                            EventSpecificSerializerMixin):
+class ActivityTagSerializer(EventSpecificSerializerMixin,
+                            serializers.ModelSerializer):
     class Meta:
         model = ActivityTag
         fields = ('url', 'id', 'name', 'is_public', 'color', 'event')
diff --git a/api/test_event.py b/api/event/tests.py
similarity index 95%
rename from api/test_event.py
rename to api/event/tests.py
index 62d77d5..147b185 100644
--- a/api/test_event.py
+++ b/api/event/tests.py
@@ -5,7 +5,7 @@ from rest_framework.test import APITestCase
 from event.models import Event, Place, ActivityTag, ActivityTemplate
 
 from api.event.serializers import ActivityTemplateSerializer, EventSerializer
-from api.test_mixins import EventBasedModelTestMixin, EventSpecificTestMixin,\
+from api.testcases import EventBasedModelTestMixin, EventSpecificTestMixin,\
         ModelTestMixin
 
 User = get_user_model()
diff --git a/api/test_mixins.py b/api/testcases.py
similarity index 94%
rename from api/test_mixins.py
rename to api/testcases.py
index 9f524d7..d91f3cb 100644
--- a/api/test_mixins.py
+++ b/api/testcases.py
@@ -54,8 +54,15 @@ class DataBaseMixin(object):
 
 class EventBasedModelTestMixin(DataBaseMixin):
     """
-    Note : need to define : `model`, `base_name`, `initial_count`,
-    `data_creation`, `instance_name`, `field_tested`, `serializer`
+    Note : need to define :
+    `model`: the model served by the API
+    `base_name`: the base_name used in the URL
+    `initial_count`: (will disappear) inital count in the db
+    `data_creation`: name in db used to create new instance
+    `instance_name`: existing instance name in the db
+        used for update/delete
+    `field_tested`: name of field tested in the update test
+    `serializer`: serialiser used for the API
 
     tests for models served by the API that are related to an event
     and whose API urls are nested under ../event/<event_id>/%model
@@ -152,7 +159,10 @@ class EventSpecificTestMixin(object):
     """
     Tests is the EventSpecifics querysets are rendered correctly
     using the API
-    Note : need to define : `model`, `root_base_name` and `event_base_name`
+    Note : need to define :
+    `model`: the concerned model serve by the API
+    `root_base_name`: the base_name used in the root-level urls
+    `event_base_name`: the base_name used in the event-level urls
 
     tests for  models served by the API that inherit EventSpecificMixin
     """