1. funcargs &
other fun
with
pytest
PyCon AU 2012
Brianna Laugher

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