How to Run Pytest Tests from a List of Test Paths

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#1

How can I select which pytest tests to run from a file?

For example, if I have a file foo.txt containing a list of tests to be executed:

tests_directory/foo.py::test_001 tests_directory/bar.py::test_some_other_test

Is there a way to select multiple tests that do not share a common pattern in their names, from different directories using pytest? While pytest -k allows for a single pattern, I need to run different combinations of tests from various files.

Is there a way to specify multiple patterns and a test file name for each pattern? Can I specify exact test paths in a file and feed that file as input to pytest? Alternatively, is there a hook function that can be used to achieve this?

I’m looking for a method to pytest run specific test based on a list of test paths provided in a file.

#2

Ofcourse! To achieve what you’re asking, you can use pytest with the --ignore and --maxfail options. This is one way to manually control which tests to run by specifying the paths you want to include.

First, create a file tests_to_run.txt containing the list of test paths like this:


tests_directory/foo.py::test_001

tests_directory/bar.py::test_some_other_test

Then, use the following command to feed the test paths from the file directly into pytest:


pytest $(cat tests_to_run.txt)

This simple method allows you to pytest run specific test cases listed in tests_to_run.txt. It’s straightforward and avoids the need for complex pattern matching.

#3

if you want something more customizable, you can create a custom pytest plugin to automatically read from your file and filter the tests to run.

Here’s how to do it. Create a file called pytest_plugins.py with the following code:

import pytest

def pytest_addoption(parser):
    parser.addoption("--testlist", action="store", default=None, help="Path to file with list of tests to run")

@pytest.hookimpl(tryfirst=True)
def pytest_collection_modifyitems(config, items):
    testlist_path = config.getoption("--testlist")
    if testlist_path:
        with open(testlist_path, 'r') as f:
            tests_to_run = set(line.strip() for line in f)
        
        items[:] = [item for item in items if f"{item.nodeid}" in tests_to_run]

Now, when running pytest, you simply pass the file like this:

pytest --testlist=tests_to_run.txt

This plugin will dynamically filter the collected tests based on the content of tests_to_run.txt, ensuring only those specific test cases are run. A very flexible way to pytest run specific test cases, especially if you have more complex test suite structures.

#4

Another approach would be to use pytest markers to group your tests in a more structured way, especially if you plan to reuse test sets frequently.

You can mark your tests in the code like this:

import pytest

@pytest.mark.test_001
def test_001():
    assert True

@pytest.mark.test_some_other_test
def test_some_other_test():
    assert True

Next, create a file called markers.txt containing the list of markers you want to run:

test_001
test_some_other_test

Then, you can use a loop to run pytest for each marker:

for marker in $(cat markers.txt); do
    pytest -m $marker
done

This way, you leverage pytest’s marker feature to pytest run specific test cases associated with each marker, giving you even more control and flexibility.