pytest-expect-test

A fixture to support expect tests (golden tests) in pytest

This code was mostly copied from ezyang/expecttest who wrote an implementation for unittest.

Installation

You can install "pytest-expect-test" via pip from PyPI:

$ pip install pytest-expect-test

Usage

Start by writing your test, printing out any interesting output, and then calling expect with an empty string

# Function we are testing
def cumulative_sum(nums):
    cum_sum = 0
    result = []
    for num in nums:
        result.append(num+cum_sum)
        cum_sum += num
    return result


def test_cumulative_sum(expect):
    print(cumulative_sum([2, 3, 5]))
    expect("""""")
    print(cumulative_sum([1, 5, 9]))
    expect("""""")

Then run:

$ pytest

Note that the test fails because we expected nothing to be printed (e.g. we passed an empty string to the expect function), but there was some text that was printed.

We can automatically fix these tests by running:

$ EXPECTTEST_ACCEPT=1 pytest

Our test will then be updated automatically so that it passes:

def test_cumulative_sum(expect):
    print(cumulative_sum([2, 3, 5]))
    expect("""\
[2, 5, 10]
""")
    print(cumulative_sum([1, 5, 9]))
    expect("""\
[1, 6, 15]
""")

Contributing

Contributions are very welcome. Tests can be run with tox, please ensure the coverage at least stays the same before you submit a pull request.

License

Distributed under the terms of the MIT license, "pytest-expect-test" is free and open source software

This pytest plugin was generated with Cookiecutter along with @hackebrot's cookiecutter-pytest-plugin template.

Issues