Funcargs and other fun with pytest

Presented at PyCon AU 2012.

Transcript

1. PyCon AU 2012 Brianna Laugher funcargs & other fun with pytest
2. pytest – all the good stuff ✔ all test styles: unittest, doctest, nose ✔ boilerplate-free style – natural asserts ✔ support for running tests distributed, boxed ✔ generate JUnit-style XML for Jenkins CI ✔ informative error reporting ✔ extensible plugins, useful builtins ✔ skip, xfail, custom markers ✔ parametrize, generate tests ✔ monkeypatch ✔ funcargs!
4. my background • using pytest seriously for ~18 months at work • really enjoying it! • how it feels to use pytest: →
8. Graphical Forecast Editor • client/server desktop application used by forecasters to generate the (text & graphical) forecasts • pilot in VIC, funding to roll out nationally, ~5 year project, 20+ new devs/testers • existing codebase of Python and C++ (used operationally in US) • home-grown test suite and runner (via GUI)
10. informative error reporting
11. informative error reporting
12. extensible • e.g. add in unittest assert methods
13. extensible • e.g. add hook for winpdb
15. skip
16. xfail
17. custom markers
19. parametrize
21. generate tests • defined once per module • list/generate data to supply to 1+ tests • way more flexible cf. py.test.mark.parametrize
22. generate generators!
24. monkeypatch
29. funcargs!
30. funcargs – idealised db example
31. funcargs – trivial django example
32. funcargs – trivial GAE examples
33. funcargs – trivial GAE examples
35. funcargs – why? • dependency injection, aka inversion of control • works a treat with TDD • very natural with mocking • encourages modular design
37. funcargs – a real DB example
38. funcargs – a real DB example
39. funcargs – to express prereq's • for when a decorator is not powerful enough
41. funcargs – to hide monkeypatch :)
43. generate + funcarg - anypython
46. pytest – the future
48. test evolution -v0
50. test evolution - v1
51. test evolution - v2
52. test evolution – v3
53. test evolution - v4
55. pytest – all the good stuff ✔ all test styles: unittest, doctest, nose ✔ boilerplate-free style – natural asserts ✔ support for running tests distributed, boxed ✔ generate JUnit-style XML for Jenkins CI ✔ informative error reporting ✔ extensible plugins, useful builtins ✔ skip, xfail, custom markers ✔ parametrize, generate tests ✔ monkeypatch ✔ funcargs!
58. • http://codespeak.net/mailman/listinfo/py-dev • testing-in-python mailing list • Stack Overflow • lead developer Holger Krekel is very responsive
59. pytest.org
60. credits, thanks, contact Comic panels from comicallyvintage.tumblr.com Bureau of Meteorology • In particular, Darius Powell introduced pytest to our project Code examples: gist.github.com/3386951 brianna@modernthings.org brianna.laugher.id.au / b.laugher@bom.gov.au @pfctdayelise