Now line is to long...

Much more readable could be:
```
self.assertDictEqual(
    data[pos], {
        'user_id': uid,
        'name': name,
        'avatar_url': 'https://intranet.stxnext.pl:443/api/images/users/{0}'.format(uid),
    }, 
    msg=(uid, name, pos)
)
```