pytest's parametrize (beginner - intermediate) anthony explains #027

today I explain pytest's parametrize which allows you to generate many tests from one test skeleton! Often referred to as table tests in other testing frameworks.

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[essamgouda]

Your pytest videos are very nice, short and straight to the point. Thank you !!

[buffetCodes]

Short, concise and accurate! Well done man.

[apdy]

The pytest.mark.parametrize decorator takes any iterable as the second parameter which made it easy for working through a lot of input and output for a game which were present in a file. Thanks for this!💜

[McSinyx]

thanks, this made me look up the doc and found really cool parametrizing examples! BTW a parameter type-hinted as float actually accept an int as well, that surprised me too the first time I saw it (the numeric tower, PEP 484)

[Sindoku]

Thanks for the names triple tip, that helps a lot!

[talalkalai]

pytest xdist video? any other parallelization mechanism for pytest?

[tejaswiniveerashetty]

How can I parametrize the whole class? Goal is to run the setup class and all the test cases for each value in the parametrized list

[apoorvagupta]

Is there any way to use the variable generated at run time ( suppose - self.id) to use as a parameter inside pytest.mark.parametrize?

[jakehobbyroyle]

Nice video, if my input to the test was a large json blob can I store this in conftest.py and import on run?

[_gunna]

The pytest.param is awesome to learn about! I love parametrizing tests at work, but it's not always immediately obvious which test case failed in a parametrized test with like ~10 cases. :--) Do you have any blog posts/videos that you've loved that dive deep into intermediate+ pytest usage? Or do i just rtfm

[adityahpatel]

This is is easy because u only have 1 input and 1 expected output. What precisely to do when u have 3 inputs and 1 output? e.g. testing a function which adds 3 numbers

[amir.hessam]

Thanks; I am fan of using fixture_id
def _fixture_id(kwargs: Dict[str, Any]) -> str:
"""Returns a user-friendly test case from the parametrized kwargs.

Parameters

kwargs : Dict[str, Any]
Key-value pairs of test resources.

Returns

str
"""

return ", ".join(f"{k} : {v}" for (k, v) in kwargs.items())

and decorate the test with
@pytest.mark.parametrize(
"kwargs",
_load_test_cases_from_json(),
ids=_fixture_id,
)