dealing with tests that cannot succeed — pytest documentation (2024)

pytest -rxXs # show extra info on xfailed, xpassed, and skipped tests

skipif¶

If you wish to skip something conditionally then you can use skipif instead.Here is an example of marking a test function to be skippedwhen run on an interpreter earlier than Python3.6:

import sys@pytest.mark.skipif(sys.version_info < (3, 7), reason="requires python3.7 or higher")def test_function(): ...

If the condition evaluates to True during collection, the test function will be skipped,with the specified reason appearing in the summary when using -rs.

You can share skipif markers between modules. Consider this test module:

# content of test_mymodule.pyimport mymoduleminversion = pytest.mark.skipif( mymodule.__versioninfo__ < (1, 1), reason="at least mymodule-1.1 required")@minversiondef test_function(): ...

You can import the marker and reuse it in another test module:

# test_myothermodule.pyfrom test_mymodule import minversion@minversiondef test_anotherfunction(): ...

For larger test suites it’s usually a good idea to have one filewhere you define the markers which you then consistently applythroughout your test suite.

Alternatively, you can use condition strings instead of booleans, but they can’t be shared between modules easilyso they are supported mainly for backward compatibility reasons.

Reference: pytest.mark.skipif

Skip all test functions of a class or module¶

You can use the skipif marker (as any other marker) on classes:

@pytest.mark.skipif(sys.platform == "win32", reason="does not run on windows")class TestPosixCalls: def test_function(self): "will not be setup or run under 'win32' platform"

If the condition is True, this marker will produce a skip result foreach of the test methods of that class.

If you want to skip all test functions of a module, you may use thepytestmark global:

# test_module.pypytestmark = pytest.mark.skipif(...)

If multiple skipif decorators are applied to a test function, itwill be skipped if any of the skip conditions is true.

Skipping files or directories¶

Sometimes you may need to skip an entire file or directory, for example if thetests rely on Python version-specific features or contain code that you do notwish pytest to run. In this case, you must exclude the files and directoriesfrom collection. Refer to Customizing test collection for moreinformation.

Skipping on a missing import dependency¶

You can skip tests on a missing import by using pytest.importorskipat module level, within a test, or test setup function.

docutils = pytest.importorskip("docutils")

If docutils cannot be imported here, this will lead to a skip outcome ofthe test. You can also skip based on the version number of a library:

docutils = pytest.importorskip("docutils", minversion="0.3")

The version will be read from the specifiedmodule’s __version__ attribute.

Summary¶

Here’s a quick guide on how to skip tests in a module in different situations:

1. Skip all tests in a module unconditionally:

pytestmark = pytest.mark.skip("all tests still WIP")

See Also

The Ultimate Guide To Skipping The Games: Master The Art Of Efficiency

2. Skip all tests in a module based on some condition:

pytestmark = pytest.mark.skipif(sys.platform == "win32", reason="tests for linux only")

3. Skip all tests in a module if some import is missing:

pexpect = pytest.importorskip("pexpect")

condition parameter¶

If a test is only expected to fail under a certain condition, you can passthat condition as the first parameter:

@pytest.mark.xfail(sys.platform == "win32", reason="bug in a 3rd party library")def test_function(): ...

Note that you have to pass a reason as well (see the parameter description atpytest.mark.xfail).

reason parameter¶

You can specify the motive of an expected failure with the reason parameter:

@pytest.mark.xfail(reason="known parser issue")def test_function(): ...

raises parameter¶

If you want to be more specific as to why the test is failing, you can specifya single exception, or a tuple of exceptions, in the raises argument.

@pytest.mark.xfail(raises=RuntimeError)def test_function(): ...

Then the test will be reported as a regular failure if it fails with anexception not mentioned in raises.

run parameter¶

If a test should be marked as xfail and reported as such but should not beeven executed, use the run parameter as False:

@pytest.mark.xfail(run=False)def test_function(): ...

This is specially useful for xfailing tests that are crashing the interpreter and should beinvestigated later.

strict parameter¶

Both XFAIL and XPASS don’t fail the test suite by default.You can change this by setting the strict keyword-only parameter to True:

@pytest.mark.xfail(strict=True)def test_function(): ...

This will make XPASS (“unexpectedly passing”) results from this test to fail the test suite.

You can change the default value of the strict parameter using thexfail_strict ini option:

[pytest]xfail_strict=true

Ignoring xfail¶

By specifying on the commandline:

pytest --runxfail

you can force the running and reporting of an xfail marked testas if it weren’t marked at all. This also causes pytest.xfail() to produce no effect.

Examples¶

Here is a simple test file with the several usages:

import pytestxfail = pytest.mark.xfail@xfaildef test_hello(): assert 0@xfail(run=False)def test_hello2(): assert 0@xfail("hasattr(os, 'sep')")def test_hello3(): assert 0@xfail(reason="bug 110")def test_hello4(): assert 0@xfail('pytest.__version__[0] != "17"')def test_hello5(): assert 0def test_hello6(): pytest.xfail("reason")@xfail(raises=IndexError)def test_hello7(): x = [] x[1] = 1

Running it with the report-on-xfail option gives this output:

example $ pytest -rx xfail_demo.py=========================== test session starts ============================platform linux -- Python 3.x.y, pytest-6.x.y, py-1.x.y, pluggy-1.x.ycachedir: $PYTHON_PREFIX/.pytest_cacherootdir: $REGENDOC_TMPDIR/examplecollected 7 itemsxfail_demo.py xxxxxxx [100%]========================= short test summary info ==========================XFAIL xfail_demo.py::test_helloXFAIL xfail_demo.py::test_hello2 reason: [NOTRUN]XFAIL xfail_demo.py::test_hello3 condition: hasattr(os, 'sep')XFAIL xfail_demo.py::test_hello4 bug 110XFAIL xfail_demo.py::test_hello5 condition: pytest.__version__[0] != "17"XFAIL xfail_demo.py::test_hello6 reason: reasonXFAIL xfail_demo.py::test_hello7============================ 7 xfailed in 0.12s ============================