Update the expected HTML content type of failing view tests.

mayan/apps/django_gpg/tests/test_views.py

@@ -32,6 +32,8 @@ class KeyViewTestCase(GenericViewTestCase):
 
         self.role.permissions.add(permission_key_download.stored_permission)
 
+        self.expected_content_type = 'application/octet-stream; charset=utf-8'
+
         response = self.get(
             viewname='django_gpg:key_download', args=(key.pk,)
         )

mayan/apps/document_signatures/tests/test_views.py

@@ -213,6 +213,8 @@ class SignaturesViewTestCase(GenericDocumentViewTestCase):
             permission_document_version_signature_download.stored_permission
         )
 
+        self.expected_content_type = 'application/octet-stream; charset=utf-8'
+
         response = self.get(
             'signatures:document_version_signature_download',
             args=(signature.pk,),

mayan/apps/documents/tests/test_events.py

@@ -52,6 +52,9 @@ class DocumentEventsTestCase(GenericDocumentViewTestCase):
         self.role.permissions.add(
             permission_document_download.stored_permission
         )
+
+        self.expected_content_type = 'image/png'
+
         self.post(
             'documents:document_download', args=(self.document.pk,),
         )