diff --git a/api/tests.py b/api/tests.py
index 04455114..3350a3fe 100644
--- a/api/tests.py
+++ b/api/tests.py
@@ -670,7 +670,7 @@ class APIEndpointsTestCase(APITestCase):
 
         def assert_more(response, url, format):
             """Assert the response is valid json when format is json"""
-            if format is "json":
+            if format == "json":
                 json.loads(response.content.decode())
 
         self.check_responses_code(
diff --git a/cotisations/test_views.py b/cotisations/test_views.py
index 1d6cbe3d..bf3a3229 100644
--- a/cotisations/test_views.py
+++ b/cotisations/test_views.py
@@ -12,13 +12,41 @@ from .models import Article, Cotisation, Facture, Paiement, Vente
 
 
 class NewFactureTests(TestCase):
+    @classmethod
+    def setUpTestData(cls):
+        cls.paiement = Paiement.objects.create(moyen="test payment")
+        cls.article_one_day = Article.objects.create(
+            name="One day",
+            prix=0,
+            duration_connection=0,
+            duration_days_connection=1,
+            duration_membership=0,
+            duration_days_membership=1,
+            available_for_everyone=True,
+        )
+        cls.article_one_month = Article.objects.create(
+            name="One mounth",
+            prix=0,
+            duration_connection=1,
+            duration_days_connection=0,
+            duration_membership=1,
+            duration_days_membership=0,
+            available_for_everyone=True,
+        )
+        cls.article_one_month_and_one_week = Article.objects.create(
+            name="One mounth and one week",
+            prix=0,
+            duration_connection=1,
+            duration_days_connection=7,
+            duration_membership=1,
+            duration_days_membership=7,
+            available_for_everyone=True,
+        )
+
+
     def tearDown(self):
         self.user.facture_set.all().delete()
         self.user.delete()
-        self.paiement.delete()
-        self.article_one_day.delete()
-        self.article_one_month.delete()
-        self.article_one_month_and_one_week.delete()
 
     def setUp(self):
         self.user = Adherent.objects.create(pseudo="testUser", email="test@example.org")
@@ -34,35 +62,6 @@ class NewFactureTests(TestCase):
             ]
         )
         self.user.save()
-
-        self.paiement = Paiement.objects.create(moyen="test payment")
-        self.article_one_day = Article.objects.create(
-            name="One day",
-            prix=0,
-            duration_connection=0,
-            duration_days_connection=1,
-            duration_membership=0,
-            duration_days_membership=1,
-            available_for_everyone=True,
-        )
-        self.article_one_month = Article.objects.create(
-            name="One mounth",
-            prix=0,
-            duration_connection=1,
-            duration_days_connection=0,
-            duration_membership=1,
-            duration_days_membership=0,
-            available_for_everyone=True,
-        )
-        self.article_one_month_and_one_week = Article.objects.create(
-            name="One mounth and one week",
-            prix=0,
-            duration_connection=1,
-            duration_days_connection=7,
-            duration_membership=1,
-            duration_days_membership=7,
-            available_for_everyone=True,
-        )
         self.client.login(username="testUser", password="plopiplop")
 
     def test_invoice_with_one_day(self):
@@ -72,7 +71,7 @@ class NewFactureTests(TestCase):
             "form-INITIAL_FORMS": 0,
             "form-MIN_NUM_FORMS": 0,
             "form-MAX_NUM_FORMS": 1000,
-            "form-0-article": 1,
+            "form-0-article": self.article_one_day.pk,
             "form-0-quantity": 1,
         }
         date = timezone.now()
@@ -94,7 +93,7 @@ class NewFactureTests(TestCase):
             "form-INITIAL_FORMS": 0,
             "form-MIN_NUM_FORMS": 0,
             "form-MAX_NUM_FORMS": 1000,
-            "form-0-article": 2,
+            "form-0-article": self.article_one_month.pk,
             "form-0-quantity": 1,
         }
         date = timezone.now()
@@ -114,9 +113,9 @@ class NewFactureTests(TestCase):
             "form-INITIAL_FORMS": 0,
             "form-MIN_NUM_FORMS": 0,
             "form-MAX_NUM_FORMS": 1000,
-            "form-0-article": 1,
+            "form-0-article": self.article_one_day.pk,
             "form-0-quantity": 7,
-            "form-1-article": 2,
+            "form-1-article": self.article_one_month.pk,
             "form-1-quantity": 1,
         }
         date = timezone.now()
@@ -137,9 +136,9 @@ class NewFactureTests(TestCase):
             "form-INITIAL_FORMS": 0,
             "form-MIN_NUM_FORMS": 0,
             "form-MAX_NUM_FORMS": 1000,
-            "form-0-article": 2,
+            "form-0-article": self.article_one_month.pk,
             "form-0-quantity": 1,
-            "form-1-article": 2,
+            "form-1-article": self.article_one_month.pk,
             "form-1-quantity": 1,
         }
         response = self.client.post(