Run Single pytest Test

23 May 2022

How to run just one test with pytest.

After you make your first test, you'll make hundreds more. But to run them all takes a lot of time. So if you're working in one corner of the code, just run the tests that you care about.

Run a single file

To run a single test file, such as pie_test.py, run:

pytest path/to/pie_test.py

If you want to run all the tests related to pie, such as pie_service_test.py and pie_model_test.py at the same time, run the same command with the substring:

pytest path/to/pie*

You can put multiple paths on that command, space-delimited.

Run a single test in the file

What if you have many different tests in the pie_test.py file, such as:

def test_one():
    # ...

def test_two():
    # ...

def test_three():
    # ...

And you only want to run test_two, you can use the -k parameter to match on function name substring:

pytest path/to/pie_test.py -k two

Now you can narrow down and run only the test you want to. Next, watch the source and re-run the test on change.