CODEWITHSUNDEEP
pythontestingpytest
nonbot
nonbot

Reputation: 983

pytest: How to pass in values and create a test fixture from command line?

I have a simple test as shown below:

# contents of test_example
def test_addition(numbers):

    assert numbers < 5

And below is my conftest

# contents of conftest
import pytest

@pytest.fixture(params=[1, 2, 3, 4])
def numbers(request):
    return request.param

However now I want to test the numbers 5 and 6but not have to explicitly hardcode that. On command line, I would like to override the numbers test fixture with the numbers 5 and 6 such that:

py.test test_example.py --numbers=[5, 6]

I would expect the result of the above invocation to overwrite the conftest numbers test fixture with my test fixture created at command line and run test_addition() on 5 and 6 only.

How would I go about doing this?

Upvotes: 1

Views: 1158

Answers (1)

sax
sax

Reputation: 3806

reading here you can

tests/conftest.py

def pytest_addoption(parser):
    parser.addoption("--numbers", action="store", dest="numbers",
                 default="1,2,3,4")

def pytest_generate_tests(metafunc):
    if 'number' in metafunc.fixturenames:
        metafunc.parametrize("number", metafunc.config.option.numbers.split(','))

tests/test_1.py

def test_numbers(number):
    assert number

so:

$ py.test tests/ -vv
=========================================
collected 4 items

test_1.py::test_numbers[1] PASSED
test_1.py::test_numbers[2] PASSED
test_1.py::test_numbers[3] PASSED
test_1.py::test_numbers[4] PASSED

and

$ py.test tests/ -vv --numbers=10,11
=========================================
collected 2 items

test_1.py::test_numbers[10] PASSED
test_1.py::test_numbers[11] PASSED

anyway please note here:

Warning:

This function must be implemented in a plugin and is called once at the beginning of a test run.

Implementing this hook from conftest.py files is strongly discouraged because conftest.py files are lazily loaded and may give strange unknown option errors depending on the directory py.test is invoked from.

so this code works if you run

py.test tests/

but not if

cd tests
py.test

Upvotes: 2

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