Running pytest test functions inside a jupyter notebook

Question

I’m working on a presentation about python testing options, and one of the technologies I want to demo is pytest. I’m planning to do the presentation from an jupyter/ipython notebook. Ideally I’d like to be able to define a test function in a cell and then use pytest to run just that function; that way I can demonstrate individual features of pytest, etc.

Is there an existing way to do this? None of the interactive features I saw in the pytest api seem to fit the bill, but I’m certainly no pytest expert. I’d be happy to write a plugin to do it, so any advice on the best approach in that direction would be great.

I did see pytest-ipynb, but it does not seem to do what I need. If that assessment is wrong, advice on how to use that would be great, too.

Asked By: abingham

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Answer 1

I created ipython_pytest for this purpose and used it in my PyCon Helsinki 2016 presentation.

You would use the tool like this:

%%pytest

def test_my_stuff():
    assert 42 == 42

Unfortunately I couldn’t find a way to make functions and classes defined in the notebook available to test functions in the test cell. I’d appreciate if someone comes up with a solution for that.

Answered By: akaihola

Answer 2

There is a similar module that looks very mature: https://github.com/chmp/ipytest

It is referenced in the module developed by @akaiola and is more active and regularly updated / maintained.

Here is an example from the Github repository (https://github.com/chmp/ipytest/blob/master/Example.ipynb)

And another one I have created recently

Answered By: Jean-Francois T.

Answer 3

My 2 cents here since I’ve already solved this issue for myself 2x and both times come back to this site. For my future self:

For a project structured in the following way

prod_folder:
* data
* code
    * run_notebook.ipynb
* tests
   * test_some_test.py

If you want to run pytest from within run_notebook.ipynb the following cell-magic worked for my purposes:

!pytest ../tests

Answered By: Aus_10

Answer 4

In Google Colab I usually do the following procedure:

Create a file name for the respective cell:

Here’s an example:

%%file test_list.py

# find the mismatched elements in list `l1` which are not in list `l2`

def solution(l1: list, l2: list) -> list:
    return [
        e
        for e in l1
        if e not in [e for e in l2]
    ]

import pytest

a = [1,2,3]
b = [3,4,None,None]
TEST_CASES = [[a,b]]

class TestCase:
    @pytest.mark.parametrize("test_case", TEST_CASES)
    def test_events(self, test_case):
        assert solution(test_case[0], test_case[1]) == [1,2]

Run pytest in another cell:

!python -m pytest test_list.py

Out:

============================= test session starts ==============================
platform linux -- Python 3.8.16, pytest-3.6.4, py-1.11.0, pluggy-0.7.1
rootdir: /content, inifile:
plugins: typeguard-2.7.1
collected 1 item                                                               

test_list.py .                                                           [100%]

=========================== 1 passed in 0.02 seconds ===========================

Answered By: Benyamin Jafari – aGn

Running pytest test functions inside a jupyter notebook

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