with patch('django.core.files.storage.Storage.open',
return_value=BytesIO(b"<epub>")):
self.assertEqual(
self.signed('/api/epub/grandchild/').content,
b"<epub>")
with patch('django.core.files.storage.Storage.open',
return_value=BytesIO(b"<epub>")):
self.assertEqual(
self.signed('/api/epub/grandchild/').content,
b"<epub>")