Funcargs and other fun with pytest

Presented at PyCon AU 2012.

Transcript

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

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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!
   

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4. my background
   ●
   using pytest seriously for ~18 months at work
   ●
   really enjoying it!
   ●
   how it feels to use pytest: →
   

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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)
   

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10. informative error reporting
    

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11. informative error reporting
    

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12. extensible
    ●
    e.g. add in unittest assert methods
    

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13. extensible
    ●
    e.g. add hook for winpdb
    

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15. skip
    

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16. xfail
    

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17. custom markers
    

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19. parametrize
    

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21. generate tests
    ●
    defined once per module
    ●
    list/generate data to supply to 1+ tests
    ●
    way more flexible cf. py.test.mark.parametrize
    

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22. generate generators!
    

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24. monkeypatch
    

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29. funcargs!
    

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30. funcargs – idealised db example
    

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31. funcargs – trivial django example
    

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32. funcargs – trivial GAE examples
    

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33. funcargs – trivial GAE examples
    

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35. funcargs – why?
    ●
    dependency injection, aka inversion of control
    ●
    works a treat with TDD
    ●
    very natural with mocking
    ●
    encourages modular design
    

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37. funcargs – a real DB example
    

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38. funcargs – a real DB example
    

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39. funcargs – to express prereq's
    ●
    for when a decorator is not powerful enough
    

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41. funcargs – to hide monkeypatch :)
    

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43. generate + funcarg - anypython
    

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46. pytest – the future
    

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48. test evolution -v0
    

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50. test evolution - v1
    

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51. test evolution - v2
    

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52. test evolution – v3
    

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53. test evolution - v4
    

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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!
    

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58. ●
    http://codespeak.net/mailman/listinfo/py-dev
    ●
    testing-in-python mailing list
    ●
    Stack Overflow
    ●
    lead developer Holger Krekel is very
    responsive
    

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59. pytest.org
    

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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
    

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