Property-based testing 101

Introduction to property-based testing concepts.

Transcript

1. Property-based testing 101
   

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2. El problema
   https://fsharpforfunandprofit.com/posts/property-based-testing/
   http://hypothesis.works/articles/what-is-hypothesis/#how-to-use-it
   TDD: hacer lo mínimo para que pase vs Generalización vs Edge cases
   

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3. Definición (I)
   Property-based tests make statements about the output of your code based on the
   input, and these statements are verified for many different possible inputs.
   Rather than writing a test that tests just a single scenario, you write tests that describe
   a range of scenarios and then let the computer explore the possibilities for you rather
   than having to hand-write every one yourself.
   

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4. A single test is run hundreds of times with randomly generated inputs (fuzzing).
   A property-based testing framework runs the same test over and over with generated
   input.
   Definición (II)
   

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6. Example-based testing
   Property-based tests are best combined with example-based tests.
   Examples help you start organizing your thoughts, and they're easier for future-you to
   read and understand when you come back to this code later.
   Humans think in examples. Programs don't extrapolate. Property-based thinking and
   property-based testing can bridge between us and the computer.
   Math, it's a tool.
   

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7. El origen
   Haskell Quickcheck: http://hackage.haskell.org/package/QuickCheck
   The programmer provides a specification of the program, in the form of properties
   which functions should satisfy, and QuickCheck then tests that the properties hold in a
   large number of randomly generated cases.
   

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8. Property-based testing en Python
   https://github.com/npryce/python-factcheck >> https://pypi.python.org/pypi/factcheck
   https://github.com/HypothesisWorks/hypothesis-python
   https://pypi.python.org/pypi/pytest-quickcheck/
   

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9. https://github.com/islomar/poc-python/tree/master/property-based-testing
   

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10. Links de interés
    ● http://blog.jessitron.com/2013/04/property-based-testing-what-is-it.html
    ● https://fsharpforfunandprofit.com/posts/property-based-testing/
    ● https://fsharpforfunandprofit.com/posts/property-based-testing-2/
    ●
    Property-based testing tools:
    https://gist.github.com/npryce/4147916
    ●
    https://blog.wearewizards.io/using-haskells-quickcheck-for-python
    ●
    TDD + QuickCheck:
    http://www.natpryce.com/articles/000795.html
    ●
    https://www.infoq.com/presentations/hypothesis-afl-property-testing
    

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