Still this kind thing

picampaign/importer/models.py

@@ -31,7 +31,7 @@ class Importer(models.Model):
     def kind(self):
         if self.url is None and self.file.name is None:
             return None
-        if self.url is '':
+        if self.url is not '' and self.url is not None:
             return 'url'
         else:
             return 'file'

picampaign/importer/tests.py

@@ -128,7 +128,7 @@ class ImporterTest(TestCase):
         importer = Importer.objects.create(
             name='test importer',
             category='repr',
-            campaign = self.campaign,
+            campaign=self.campaign,
         )
         self.assertEqual(importer.kind(), None)
         importer.file = 'a'
@@ -145,7 +145,7 @@ class ImporterTest(TestCase):
         importer = Importer.objects.create(
             name='test importer',
             category='repr',
-            campaign = self.campaign,
+            campaign=self.campaign,
             file=json_file,
             url=''
         )