add credentials to TestHandlerBase #3481
Description
Token/credentials are hardcoded in a few tests, it might be better to add them in a single place so they can be reused, maybe part of TestHandlerBase. For example: https://github.com/qiita-spots/qiita/blob/master/qiita_db/test/test_software.py#L695-L697