I'll enthusiastically second py.test. It's well documented, well supported, and well thought out. More importantly though, the details are just brilliantly done

I'll enthusiastically second py.test. It's well documented, well supported, and well thought out. More importantly though, the details are just brilliantly done. For example: showing the values of local variables in an error traceback always saves me a ton of time. I don't know why this isn't the default option. Alternatively, you can pass --pdb to just run the debugger exactly when a test crashes, so you can inspect the contents. Another example is how it prints out details on assertions (e.g. "the left was this and the right was this") and not just "AssertionError". On top of that, for complex data structures, it will diff them and point out exactly what parts of the structure are matching and what parts are not matching, which again saves a ton of time from firing up a debugger and doing it by hand. For more esoteric options, I like this pycon talk: https://www.youtube.com/watch?v=jmsk1QZQEvQ https://www.youtube.com/watch?v=jmsk1QZQEvQ