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A pytest plugin that allows multiple failures per test.

Project description


A pytest plugin that allows multiple failures per test.

This pytest plugin was a rewrite and a rename of pytest-expect.


Note: Requires pytest 6.0 or above.

From PyPI:

$ pip install pytest-check

Or from github.

$ pip install git+


Example using import:

import pytest_check as check

def test_example():
    a = 1
    b = 2
    c = [2, 4, 6]
    check.greater(a, b)
    check.less_equal(b, a)
    check.is_in(a, c, "Is 1 in the list")
    check.is_not_in(b, c, "make sure 2 isn't in list")

Test results:

=================================== FAILURES ===================================
_________________________________ test_example _________________________________
assert 1 > 2, line 14, in test_example() -> check.greater(a, b)
assert 2 <= 1, line 15, in test_example() -> check.less_equal(b, a)
FAILURE: Is 1 in the list
assert 1 in [2, 4, 6], line 16, in test_example() -> check.is_in(a, c, "Is 1 in the list")
FAILURE: make sure 2 isn't in list
assert 2 not in [2, 4, 6], line 17, in test_example() -> check.is_not_in(b, c, "make sure 2 isn't in list")
Failed Checks: 4
=========================== 1 failed in 0.11 seconds ===========================

Example using fixture:

def test_example(check):
    a = 1
    b = 2
    c = [2, 4, 6]
    check.greater(a, b)
    check.less_equal(b, a)
    check.is_in(a, c, "Is 1 in the list")
    check.is_not_in(b, c, "make sure 2 isn't in list")

validation functions

  • check.equal - a == b
  • check.not_equal - a != b
  • check.is_ - a is b
  • check.is_not - a is not b
  • check.is_true - bool(x) is True
  • check.is_false - bool(x) is False
  • check.is_none - x is None
  • check.is_not_none - x is not None
  • check.is_in - a in b
  • check.is_not_in - a not in b
  • check.is_instance - isinstance(a, b)
  • check.is_not_instance - not isinstance(a, b)
  • check.almost_equal - a == pytest.approx(b, rel, abs) see at: pytest.approx
  • check.not_almost_equal - a != pytest.approx(b, rel, abs) see at: pytest.approx
  • check.greater - a > b
  • check.greater_equal - a >= b
  • check.less - a < b
  • check.less_equal - a <= b
  • check.raises - func raises given exception similar to pytest.raises

Defining your own check functions

The @check_func decorator allows you to wrap any test helper that has an assert statement in it to be a non-blocking assert function.

from pytest_check import check_func

def is_four(a):
    assert a == 4

def test_all_four():

The above will result in:

________________________________ test_all_four _________________________________
FAILURE: assert 1 == 4, line 8, in test_all_four() -> is_four(1)
FAILURE: assert 2 == 4, line 9, in test_all_four() -> is_four(2)
FAILURE: assert 3 == 4, line 10, in test_all_four() -> is_four(3)
Failed Checks: 3
=========================== 1 failed in 0.12 seconds ===========================

Using check as a context manager

You can use the check() context manager to wrap any assert that you want to continue after in a test.

from pytest_check import check

def test_context_manager():
    with check:
        x = 3
        assert 1 < x < 4

Within any with check:, however, you still won't get past the assert statement, so you will need to use multiple with check: blocks for multiple asserts:

    def test_multiple_failures():
        with check: assert 1 == 0
        with check: assert 1 > 2
        with check: assert 1 < 5 < 4

Using raises as a context manager

raises can also be used as a context manager:

from pytest_check import raises

def test_context_manager():
    with raises(AssertionError):
        x = 3
        assert 1 < x < 4

Just like with check as a context manager, execution won't proceed past the first line that throws an error, even if it is successfully captured and logged by Pytest Check. Break your assertions over multiple uses of raises if you encounter this problem.

maxfail behavior

Setting -x or --maxfail=1 will cause this plugin to abort testing after the first failed check.

Setting -maxfail=2 or greater will turn off any handling of maxfail within this plugin and the behavior is controlled by pytest.

In other words, the maxfail count is counting tests, not checks. The exception is the case of 1, where we want to stop on the very first failed check.


Contributions are very welcome. Tests can be run with tox. Test coverage is now 100%. Please make sure to keep it at 100%. If you have an awesome pull request and need help with getting coverage back up, let me know.


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


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



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