On 8/20/17 9:32 PM, Neil Girdhar wrote:
> This question describes an example of the
> problem:
> https://stackoverflow.com/questions/8416208/in-python-is-there-a-good-idiom-for-using-context-managers-in-setup-teardown.
> You want to invoke a context manager in your setup/tearing-down, but
> the easiest way to do that is to override run, which seems ugly.
>
> Why not add two methods to unittest.TestCase whose default
> implementations are given below:
>
> class TestCase:
>
> @contextmanager
> def method_context(self):
> self.setUp()
> try:
> yield
> finally:
> self.tearDown()
>
> @contextmanager
> def class_context(self):
> self.setUpClass()
> try:
> yield
> finally:
> self.tearDown()
>
>
> Then, if for example someone wants to use a context manager in setUp,
> they can do so:
>
> class SomeTest(TestCase):
>
> @contextmanager
> def method_context(self):
> with np.errstate(all='raise'):
> with super().method_context():
> yield
>
> Best,
>
> Neil
>
>
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I've achieved a similar effect with this:
def setup_with_context_manager(testcase, cm):
"""Use a contextmanager to setUp a test case.
If you have a context manager you like::
with ctxmgr(a, b, c) as v:
# do something with v
and you want to have that effect for a test case, call this
function from
your setUp, and it will start the context manager for your test,
and end it
when the test is done::
def setUp(self):
self.v = setup_with_context_manager(self, ctxmgr(a, b, c))
def test_foo(self):
# do something with self.v
"""
val = cm.__enter__()
testcase.addCleanup(cm.__exit__, None, None, None)
return val
I think the use is easier than yours, which needs too much super and
@contextmanager boilerplate.
--Ned.
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