Change the way we mock TestLoadImage.test_good_url
Change the way we mock TestLoadImage.test_good_url

Less mocking is good. Also I couldn't figure out how to mock StringIO
anymore.

Lucaszw/DIGITS,jmancewicz/DIGITS,Deepomatic/DIGITS,dongjoon-hyun/DIGITS,bygreencn/DIGITS,TimZaman/DIGITS,ethantang95/DIGITS-GAN,Deepomatic/DIGITS,Deepomatic/DIGITS,bygreencn/DIGITS,jmancewicz/DIGITS,Deepomatic/DIGITS,ethantang95/DIGITS,Lucaszw/DIGITS,gheinrich/DIGITS-GAN,ethantang95/DIGITS-GAN,dongjoon-hyun/DIGITS,bygreencn/DIGITS,bygreencn/DIGITS,ethantang95/DIGITS,brainstorm-ai/DIGITS,gheinrich/DIGITS-GAN,ethantang95/DIGITS-GAN,jmancewicz/DIGITS,jmancewicz/DIGITS,Lucaszw/DIGITS,dongjoon-hyun/DIGITS,ethantang95/DIGITS-GAN,brainstorm-ai/DIGITS,TimZaman/DIGITS,gheinrich/DIGITS-GAN,brainstorm-ai/DIGITS,Lucaszw/DIGITS,TimZaman/DIGITS,ethantang95/DIGITS,dongjoon-hyun/DIGITS,ethantang95/DIGITS,gheinrich/DIGITS-GAN,brainstorm-ai/DIGITS,TimZaman/DIGITS