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pytest-twisted 1.6

A twisted plugin for py.test.

pytest-twisted is a plugin for pytest, which allows to test code, which uses the twisted framework. test functions can return Deferred objects and pytest will wait for their completion with this plugin.


Install the plugin with:

pip install pytest-twisted

Using the plugin

The plugin is available after installation and can be disabled using -p no:twisted.


Using twisted.internet.defer.inlineCallbacks as a decorator for test functions, which take funcargs, does not work. Please use pytest.inlineCallbacks instead:

def test_some_stuff(tmpdir):
    res = yield threads.deferToThread(os.listdir, tmpdir.strpath)
    assert res == []

Waiting for deferreds in fixtures

pytest.blockon allows fixtures to wait for deferreds:

def val():
    d = defer.Deferred()
    reactor.callLater(1.0, d.callback, 10)
    return pytest.blockon(d)

The twisted greenlet

Some libraries (e.g. corotwine) need to know the greenlet, which is running the twisted reactor. It’s available from the twisted_greenlet funcarg. The following code can be used to make corotwine work with pytest-twisted:

@pytest.fixture(scope="session", autouse=True)
def set_MAIN(request, twisted_greenlet):
    from corotwine import protocol
    protocol.MAIN = twisted_greenlet

That’s all.

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