How to pass arguments in pytest by command line

Solution 1:

In your pytest test, don't use @pytest.mark.parametrize:

def test_print_name(name):
    print ("Displaying name: %s" % name)

In conftest.py:

def pytest_addoption(parser):
    parser.addoption("--name", action="store", default="default name")


def pytest_generate_tests(metafunc):
    # This is called for every test. Only get/set command line arguments
    # if the argument is specified in the list of test "fixturenames".
    option_value = metafunc.config.option.name
    if 'name' in metafunc.fixturenames and option_value is not None:
        metafunc.parametrize("name", [option_value])

Then you can run from the command line with a command line argument:

pytest -s tests/my_test_module.py --name abc

Solution 2:

Use the pytest_addoption hook function in conftest.py to define a new option.
Then use pytestconfig fixture in a fixture of your own to grab the name.
You can also use pytestconfig from a test to avoid having to write your own fixture, but I think having the option have it's own name is a bit cleaner.

# conftest.py

def pytest_addoption(parser):
    parser.addoption("--name", action="store", default="default name")

# test_param.py 

import pytest

@pytest.fixture()
def name(pytestconfig):
    return pytestconfig.getoption("name")

def test_print_name(name):
        print(f"\ncommand line param (name): {name}")

def test_print_name_2(pytestconfig):
    print(f"test_print_name_2(name): {pytestconfig.getoption('name')}")

# in action

$ pytest -q -s --name Brian test_param.py

test_print_name(name): Brian
.test_print_name_2(name): Brian
.

Solution 3:

I stumbled here looking for how to pass an argument, but I wanted to avoid parameterizing the test. The answers above do perfectly well address the exact question of parameterizing a test from the command line, but I would like to offer an alternative way to pass a command line argument to particular tests. The method below uses a fixture and skips the test if the fixture is specified but the argument is not:

test.py:

def test_name(name):
    assert name == 'almond'

conftest.py:

import pytest

def pytest_addoption(parser):
    parser.addoption("--name", action="store")

@pytest.fixture(scope='session')
def name(request):
    name_value = request.config.option.name
    if name_value is None:
        pytest.skip()
    return name_value

Examples:

$ py.test tests/test.py
=========================== test session starts ============================
platform linux -- Python 3.7.1, pytest-4.0.0, py-1.7.0, pluggy-0.8.0
rootdir: /home/ipetrik/dev/pytest_test, inifile:
collected 1 item

tests/test.py s                                                      [100%]

======================== 1 skipped in 0.06 seconds =========================

$ py.test tests/test.py --name notalmond
=========================== test session starts ============================
platform linux -- Python 3.7.1, pytest-4.0.0, py-1.7.0, pluggy-0.8.0
rootdir: /home/ipetrik/dev/pytest_test, inifile:
collected 1 item

tests/test.py F                                                      [100%]

================================= FAILURES =================================
________________________________ test_name _________________________________

name = 'notalmond'

    def test_name(name):
>       assert name == 'almond'
E       AssertionError: assert 'notalmond' == 'almond'
E         - notalmond
E         ? ---
E         + almond

tests/test.py:5: AssertionError
========================= 1 failed in 0.28 seconds =========================

$ py.test tests/test.py --name almond
=========================== test session starts ============================
platform linux -- Python 3.7.1, pytest-4.0.0, py-1.7.0, pluggy-0.8.0
rootdir: /home/ipetrik/dev/pytest_test, inifile:
collected 1 item

tests/test.py .                                                      [100%]

========================= 1 passed in 0.03 seconds =========================

Solution 4:

All you have to do is use pytest_addoption() in conftest.py and finally use request fixture:

# conftest.py

from pytest import fixture


def pytest_addoption(parser):
    parser.addoption(
        "--name",
        action="store"
    )

@fixture()
def name(request):
    return request.config.getoption("--name")

And now you can run your test

def my_test(name):
    assert name == 'myName'

using:

pytest --name myName