more robust tests

kfet/forms.py

@@ -2,7 +2,6 @@
 
 from datetime import timedelta
 from decimal import Decimal
-from itertools import chain
 
 from django import forms
 from django.core.exceptions import ValidationError
@@ -145,7 +144,7 @@ class UserGroupForm(forms.ModelForm):
     def clean_groups(self):
         kfet_groups = self.cleaned_data.get('groups')
         other_groups = self.instance.groups.exclude(name__icontains='K-Fêt')
-        return chain(kfet_groups, other_groups)
+        return list(kfet_groups) + list(other_groups)
 
     class Meta:
         model = User

kfet/tests/test_forms.py

@@ -28,7 +28,11 @@ class UserGroupFormTests(TestCase):
         """Only K-Fêt groups are selectable."""
         form = UserGroupForm(instance=self.user)
         groups_field = form.fields['groups']
-        self.assertEqual(len(groups_field.choices), len(self.kfet_groups))
+        self.assertQuerysetEqual(
+            groups_field.queryset,
+            [repr(g) for g in self.kfet_groups],
+            ordered=False,
+        )
 
     def test_keep_others(self):
         """User stays in its non-K-Fêt groups."""
@@ -45,4 +49,8 @@ class UserGroupFormTests(TestCase):
 
         form.is_valid()
         form.save()
-        self.assertEqual(len(user.groups.all()), 1+len(self.kfet_groups))
+        self.assertQuerysetEqual(
+            user.groups.all(),
+            [repr(g) for g in [self.other_group] + self.kfet_groups],
+            ordered=False,
+        )