Muda forma que o assert é feito

sapl/test_general.py

@@ -7,24 +7,26 @@ from .settings import SAPL_APPS
 
 pytestmark = pytest.mark.django_db
 
+sapl_appconfs = [apps.get_app_config(n) for n in SAPL_APPS]
+
 
 def test_charfiled_textfield():
-    for model in apps.get_models():
-        fields = model._meta.local_fields
-        for field in fields:
+    for app in sapl_appconfs:
+        for model in app.get_models():
+            fields = model._meta.local_fields
+            for field in fields:
                 if isinstance(field, (CharField, TextField)):
                     msg = 'Model = %s || Field = %s - %s - %s' % (
                            model.__name__,
                            field.attname,
                            type(field).__name__,
                            field.null)
-                    raise AssertionError(msg)
+                    assert not field.null, msg
 
 
 def test_str_sanity():
     # this simply a sanity check
     # __str__ semantics is not considered and should be tested separetely
-    sapl_appconfs = [apps.get_app_config(n) for n in SAPL_APPS]
     for app in sapl_appconfs:
         for model in app.get_models():
             obj = mommy.prepare(model)