如何在运行时跳过整个 Python 'unittest' 模块？

Question

I would like my Python unittest module to tell the test runner to skip it entirety under some situations (such as being unable to import a module or locate a critical resource).

I can use @unittest.skipIf(...) to skip a unittest.TestCase class, but how do I skip the entire module ? Applying skips to every class is not sufficient because the class definitions themselves could cause exceptions if a module fails to import.

Answer 1

If you look at the definition of unittest.skipIf and unittest.skip , you can see that the key is doing raise unittest.SkipTest(reason) when the test is executed. If you're okay with having it show up as skipped test instead of several in the testrunner, you can simply raise unittest.SkipTest yourself on import:

import unittest
try:
    # do thing
except SomeException:
    raise unittest.SkipTest("Such-and-such failed. Skipping all tests in foo.py")

Running with nosetests -v gives:

Failure: SkipTest (Such-and-such failed. Skipping all tests in foo.py) ... SKIP:
Such-and-such failed. Skipping all tests in foo.py

----------------------------------------------------------------------
Ran 1 test in 0.002s

OK (SKIP=1)

Answer 2

I found that using skipTest in setUp worked well. If you need a module imported, you use a try block to set eg module_failed = True, and in setUp call skipTest if it's set. This reports the correct number of test skips with only a short try block needed:

import unittest

try:
    import my_module
    module_failed = False
except ImportError:
    module_failed = True

class MyTests(unittest.TestCase):
    def setUp(self):
        if module_failed:
            self.skipTest('module not tested')

    def test_something(self):
            #...

Answer 3

After looking at the other answers here, this is the best answer I've come up with. It's ugly, embedding the whole test suite in the exception handling, but it appears to do what you want. Specifically skipping the tests when the imports don't work.

Assuming you're talking about using nosetests -x for running the tests it should carry on past the tests that skip, at least it appeared to when I tried it.

import unittest
try:
    import PyQt4
    # the rest of the imports


    # actual tests go here.
    class TestDataEntryMixin(unittest.TestCase):
        def test_somefeature(self):
            # ....

except ImportError, e:
    if e.message.find('PyQt4') >= 0:
        class TestMissingDependency(unittest.TestCase):

            @unittest.skip('Missing dependency - ' + e.message)
            def test_fail():
                pass
    else:
        raise

if __name__ == '__main__':
    unittest.main()

If the import fails it replaces the test run with a single test that simply skips. I've also attempted to make sure that it doesn't swallow any exceptions unintentionally. This solution owes a lot to all the other answers and comments to the question.

If you run it in verbose mode you will see this when it skips,

test_fail (test_openihm_gui_interface_mixins.TestMissingDependency) ... skipped 'Missing dependency - No module named PyQt4'

Answer 4

@unittest.skip('comments_for_skipping_unit_tests')
class MyTests(unittest.TestCase):
def setUp(self):
    pass

def test_something(self):

You can skip the whole unit test class by using the @unittest.skip decorator.

Answer 5

Try defining a custom load_tests function in your module:

import unittest
try:
    (testcases)
except ImportError as e:
    def load_tests(*args, **kwargs):
        print("Failed to load tests: skipping")
        return unittest.TestSuite() # no tests

Answer 6

The solution proposed by otus works and is easier than the accepted solution in my opinion. But there is at least one downside. If you query my_module in a decorator to skip a single test such as

@unittest.skipIf(my_module.support_foo, 'foo not supported')
def test_foo(self):
...

you will get a NameError: name 'my_module' is not defined . The solution is put the skip inside the function definition:

def test_foo(self):
    if not my_module.support_foo:
        self.skipTest('foo not supported')

Answer 7

For Python 2.7+ (or using the unittest2 backport):

...

import unittest

def setUpModule():
    try:
        import something
    except ImportError as err:
        raise unittest.SkipTest(str(err))

class Tests(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        try:
            import something
        except ImportError as err:
            raise unittest.SkipTest(str(err))
...

Answer 8

It might be dirty to put all the unittest.TestCase subclass definitions in a try...except block, but it would work:

import unittest
try:
    import eggs
    class Spam(unittest.TestCase):
        pass
    class Ham(unittest.TestCase):
        pass
    # ...
except ImportError:
    # print 'could not import eggs'
    pass

None of the sub-classes would be defined if the eggs import fails and all those classes ( Spam, Ham, etc. ) get skipped. It would not be reflected in the output (good or bad depending on what you want).

Answer 9

Combining the mentioned answers and using this answer :

import unittest
def module_exists(module_name):
    try:
        __import__(module_name)
    except ImportError:
        return False
    else:
        return True

class TestClass(unittest.TestCase):

    @unittest.skipUnless(module_exists("moduleA"), 'ModuleA not installed')
    def test_something(self):
        # test something with moduleA

Answer 10

You can skip the whole class just like skipping individual methods. Documentation

@unittest.skip("showing class skipping")
class MySkippedTestCase(unittest.TestCase):
    def test_not_run(self):
        pass

Answer 11

So this question is nearly a decade old, and still applicable, However. none of the other answers addressed the problem I was having today - decorators on the tests coming from the missing library, In this case, it was hypothesis and its decorators like @given ... So I was forced to whip up this less-than-friendly alternative:

try:
    from hypothesis import assume, example, given, strategies as st
    hypothesis_missing = False
except ImportError:
    hypothesis_missing = True
    def whatever(*args, **kwargs):
        if args or kwargs:
            return whatever
        raise ImportError("Requires hypothesis library")
    example = given = whatever
    # Then this part is ickier to be py2.7 compatible
    from six import add_move, MovedModule
    add_move(MoveModule('mock', 'mock', 'unittest.mock'))
    from six.moves import mock
    st = mock.Mock()  # Without this, things like st.integers() fail

A Python3-native solution would just tighten it up a little:

  import unittest
  st = unittest.mock.Mock()

Then on each testing class (ugh) I needed:

@unittest.skipIf(hypothesis_missing, "Requires hypothesis library")

IMPORTANT NOTE: Without the skipIf , the tests will sometimes silently pass - the raise ImportError in whatever() only caught about half of them in my very limited testing.

Answer 12

If you are just looking to skip an entire module/submodule then place the following code in the relevant __init__.py . Like the other solutions, this will have one message for all skipped tests.

import unittest

raise unittest.SkipTest("Don't run these tests because x, y, and z")