You can skip or “xfail” test functions, either by marking functions through a decorator or by calling the pytest.skip|xfail helpers. A skip means that you expect your test to pass unless a certain configuration or condition (e.g. wrong Python interpreter, missing dependency) prevents it to run. And xfail means that you expect your test to fail because there is an implementation problem. Counting and listing xfailing tests separately helps to maintain a list of implementation problems and you can provide info such as a bug number or a URL to provide a human readable problem context.
Usually detailed information about skipped/xfailed tests is not shown to avoid cluttering the output. You can use the -r option to see details corresponding to the “short” letters shown in the test progress:
py.test -rxs # show extra info on skips and xfail tests
Here is an example for marking a test function to be skipped when run on a Python3 interpreter:
@pytest.mark.skipif("sys.version_info >= (3,0)")
def test_function():
...
During test function setup the skipif condition is evaluated by calling eval(expr, namespace). The namespace contains the sys and os modules and the test config object. The latter allows you to skip based on a test configuration value e.g. like this:
@pytest.mark.skipif("not config.getvalue('db')")
def test_function(...):
...
Create a shortcut for your conditional skip decorator at module level like this:
win32only = pytest.mark.skipif("sys.platform != 'win32'")
@win32only
def test_function():
...
As with all function marking you can do it at whole class- or module level. Here is an example for skipping all methods of a test class based on platform:
class TestPosixCalls:
pytestmark = pytest.mark.skipif("sys.platform == 'win32'")
def test_function(self):
"will not be setup or run under 'win32' platform"
The pytestmark decorator will be applied to each test function. If your code targets python2.6 or above you can equivalently use the skipif decorator on classes:
@pytest.mark.skipif("sys.platform == 'win32'")
class TestPosixCalls:
def test_function(self):
"will not be setup or run under 'win32' platform"
It is fine in general to apply multiple “skipif” decorators on a single function - this means that if any of the conditions apply the function will be skipped.
You can use the xfail marker to indicate that you expect the test to fail:
@pytest.mark.xfail
def test_function():
...
This test will be run but no traceback will be reported when it fails. Instead terminal reporting will list it in the “expected to fail” or “unexpectedly passing” sections.
By specifying on the commandline:
pytest --runxfail
you can force the running and reporting of an xfail marked test as if it weren’t marked at all.
Same as with skipif you can also selectively expect a failure depending on platform:
@pytest.mark.xfail("sys.version_info >= (3,0)")
def test_function():
...
You can also avoid running an “xfail” test at all or specify a reason such as a bug ID or similar. Here is a simple test file with usages:
import pytest
xfail = pytest.mark.xfail
@xfail
def 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
def test_hello5():
pytest.xfail("reason")
Running it with the report-on-xfail option gives this output:
example $ py.test -rx xfail_demo.py
=========================== test session starts ============================
platform linux2 -- Python 2.6.5 -- pytest-2.0.0.dev31
test path 1: xfail_demo.py
xfail_demo.py xxxxx
========================= short test summary info ==========================
XFAIL xfail_demo.py::test_hello
XFAIL xfail_demo.py::test_hello2
reason: [NOTRUN]
XFAIL xfail_demo.py::test_hello3
condition: hasattr(os, 'sep')
XFAIL xfail_demo.py::test_hello4
bug 110
XFAIL xfail_demo.py::test_hello5
reason: reason
======================== 5 xfailed in 0.04 seconds =========================
If you cannot declare xfail-conditions at import time you can also imperatively produce an XFail-outcome from within test or setup code. Example:
def test_function():
if not valid_config():
pytest.xfail("unsuppored configuration")
You can use the following import helper at module level or within a test or test setup function:
docutils = pytest.importorskip("docutils")
If docutils cannot be imported here, this will lead to a skip outcome of the test. You can also skip dependeing if if a library does not come with a high enough version:
docutils = pytest.importorskip("docutils", minversion="0.3")
The version will be read from the specified module’s __version__ attribute.
If for some reason you cannot declare skip-conditions you can also imperatively produce a Skip-outcome from within test or setup code. Example:
def test_function():
if not valid_config():
pytest.skip("unsuppored configuration")