pytest-raises

A pytest plugin implementation of pytest.raises as a pytest.mark fixture

Features

Adds functionality for marking tests with a pytest.mark.raises fixture, which functions similarly to using with pytest.raises

Requirements

python 2.7 or above
pytest 2.8.1 or above

Installation

You can install "pytest-raises" via pip from PyPI

$ pip install pytest-raises

Usage

Marking a test with the @pytest.mark.raises() decorator will mark that the code the test executes is expected to raise an error. This is different from @pytest.mark.xfail() as it does not mean the test itself might fail, but instead that the "pass" for the test is that the code raises an error.

It accepts an exception keyword argument, which is the class of error expected to be raised.

It will allow tests which raise errors to pass. The main usage is to assert that an error of a specific type is raise.

A very simple example is:

import pytest

class SomeException(Exception):
    pass

class AnotherException(Exception):
    pass

@pytest.mark.raises(exception = SomeException)
def test_mark_raises_named():
    raise SomeException('the message')

@pytest.mark.raises()
def test_mark_raises_general():
    raise AnotherException('the message')

A more useful example using test parametrization is:

import pytest

class SomeException(Exception):
    pass

class AnotherException(Exception):
    pass

@pytest.mark.parametrize('error', [
    None,
    pytest.mark.raises(SomeException('the message'), exception=SomeException),
    pytest.mark.raises(AnotherException('the message'), exception=AnotherException),
    pytest.mark.raises(Exception('the message')),
])
def test_mark_raises(error):
    if error:
        raise error

All of these tests pass. These examples are actual tests for this plugin.

License

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

Issues

If you encounter any problems, please file an issue along with a detailed description.

zonnepanelendelen / pytest-raises