`approvaltests` is the Python port of ApprovalTests, an open source
assertion/verification library to aid testing.

You can use ApprovalTests to verify objects that require more than a
simple assert including long strings, large arrays, and complex hash
structures and objects. ApprovalTests really shines when you need a more
granular look at the test failure. Sometimes, trying to find a small
difference in a long string printed to STDOUT is just too hard!
ApprovalTests solves this problem by providing reporters which let you
view the test results in one of many popular diff utilities.

Homepage:
https://approvaltests.com/
