a py.test plugin that re-runs failed tests up to -n times to eliminate flakey failures
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README.rst

pytest-rerunfailures

pytest-rerunfailures is a plugin for py.test that re-runs tests to eliminate intermittent failures.

License PyPI Travis

Requirements

You will need the following prerequisites in order to use pytest-rerunfailures:

  • Python 2.7, 3.4, 3.5, 3.6, 3.7, PyPy, or PyPy3
  • pytest 2.8.7 or newer

Installation

To install pytest-rerunfailures:

$ pip install pytest-rerunfailures

Re-run all failures

To re-run all test failures, use the --reruns command line option with the maximum number of times you'd like the tests to run:

$ pytest --reruns 5

Failed fixture or setup_class will also be re-executed.

To add a delay time between re-runs use the --reruns-delay command line option with the amount of seconds that you would like wait before the next test re-run is launched:

$ pytest --reruns 5 --reruns-delay 1

Re-run individual failures

To mark individual tests as flaky, and have them automatically re-run when they fail, add the flaky mark with the maximum number of times you'd like the test to run:

@pytest.mark.flaky(reruns=5)
def test_example():
    import random
    assert random.choice([True, False])

Note that when teardown fails, two reports are generated for the case, one for the test case and the other for the teardown error.

You can also specify the re-run delay time in the marker:

@pytest.mark.flaky(reruns=5, reruns_delay=2)
def test_example():
    import random
    assert random.choice([True, False])

Output

Here's an example of the output provided by the plugin when run with --reruns 2 and -r aR:

test_report.py RRF

================================== FAILURES ==================================
__________________________________ test_fail _________________________________

    def test_fail():
>       assert False
E       assert False

test_report.py:9: AssertionError
============================ rerun test summary info =========================
RERUN test_report.py::test_fail
RERUN test_report.py::test_fail
============================ short test summary info =========================
FAIL test_report.py::test_fail
======================= 1 failed, 2 rerun in 0.02 seconds ====================

Note that output will show all re-runs. Tests that fail on all the re-runs will be marked as failed.

Compatibility

  • This plugin may not be used with class, module, and package level fixtures.
  • This plugin is not compatible with pytest-xdist's --looponfail flag.
  • This plugin is not compatible with the core --pdb flag.

Resources

Development

  • Test execution count can be retrieved from the execution_count attribute in test item's object. Example:
@hookimpl(tryfirst=True, hookwrapper=True)
def pytest_runtest_makereport(item, call):
    print(item.execution_count)