** Caution: cranky curmudgeonly opinionated comment ahead: ** unitest is such an ugly Java-esque static mess of an API that there's really no point in trying to clean it up and make it more pythonic -- go off and use pytest and be happier. -CHB On Tue, Aug 22, 2017 at 5:42 AM, Nick Coghlan <ncoghlan@gmail.com> wrote:

On 22 August 2017 at 15:34, Nick Coghlan <ncoghlan@gmail.com> wrote:

...

On 21 August 2017 at 11:32, Neil Girdhar <mistersheik@gmail.com> 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.

Using context managers when you can't use a with statement is one of the main use cases for contextlib.ExitStack():

def setUp(self): self._resource_stack = stack = contextlib.ExitStack() self._resource = stack.enter_context(MyResource())

def tearDown(self): self._resource_stack.close()

I posted that as an additional answer to the question: https://stackoverflow.com/questions/8416208/in-python- is-there-a-good-idiom-for-using-context-managers-in- setup-teardown/45809502#45809502

Sjoerd pointed out off-list that this doesn't cover the case where you're acquiring multiple resources and one of the later acquisitions fails, so I added the ExitStack idiom that covers that case (using stack.pop_all() as the last operation in a with statement):

def setUp(self): with contextlib.ExitStack() as stack: self._resource1 = stack.enter_context(GetResource()) self._resource2 = stack.enter_context(GetOtherResource()) # Failures before here -> immediate cleanup self.addCleanup(stack.pop_all().close) # Now cleanup won't happen until the cleanup functions run

I also remember that using addCleanup lets you avoid defining tearDown entirely.

Cheers, Nick.

-- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/

-- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception Chris.Barker@noaa.gov

** Caution: cranky curmudgeonly opinionated comment ahead: ** unitest is such an ugly Java-esque static mess of an API that there's really no point in trying to clean it up and make it more pythonic -- go off and use pytest and be happier. -CHB On Tue, Aug 22, 2017 at 5:42 AM, Nick Coghlan <ncoghlan@gmail.com> wrote:

On 22 August 2017 at 15:34, Nick Coghlan <ncoghlan@gmail.com> wrote:

...

On 21 August 2017 at 11:32, Neil Girdhar <mistersheik@gmail.com> 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.

Using context managers when you can't use a with statement is one of the main use cases for contextlib.ExitStack():

def setUp(self): self._resource_stack = stack = contextlib.ExitStack() self._resource = stack.enter_context(MyResource())

def tearDown(self): self._resource_stack.close()

I posted that as an additional answer to the question: https://stackoverflow.com/questions/8416208/in-python- is-there-a-good-idiom-for-using-context-managers-in- setup-teardown/45809502#45809502

Sjoerd pointed out off-list that this doesn't cover the case where you're acquiring multiple resources and one of the later acquisitions fails, so I added the ExitStack idiom that covers that case (using stack.pop_all() as the last operation in a with statement):

def setUp(self): with contextlib.ExitStack() as stack: self._resource1 = stack.enter_context(GetResource()) self._resource2 = stack.enter_context(GetOtherResource()) # Failures before here -> immediate cleanup self.addCleanup(stack.pop_all().close) # Now cleanup won't happen until the cleanup functions run

I also remember that using addCleanup lets you avoid defining tearDown entirely.

Cheers, Nick.

-- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/

-- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception Chris.Barker@noaa.gov