Django/Python Unit Testing: Let exceptions rise

Question

I'm debugging a unit test failure whereby an exception is raised from the guts of some libraries; many exceptions. I'm using ipdb from the commandline to debug it.

when running ./manage.py test path.to.test and the exception happens, the test runner catches the exception, prints a stack trace and marks the test failed or whatever. I get why this is useful, rather than letting the exception rise.

In my case, I want it to rise so ipdb catches it and lands me in a nice position to move up/down frames and debug the issues. I don't want to keep wrapping tests in try or putting ipdb.set_trace() calls where the exceptions are thrown. It is a pain and it is slowing down debugging. Ordinarily this isn't an issue, but today it is.

Q: Can I stop the test runner catching the exception so ipdb catches it instead without code modifications?

I feel like there should be a way to do this, as it would be very helpful when debugging, but I have missed it somewhere along the line.

(Ps, Python 2.7, Django 1.6 sadface)

Is using pytest as your runner an option? docs.pytest.org/en/latest/… It has a specific option for bubbling to pdb. — Matt Seymour
– Matt Seymour, Commented Jul 12, 2017 at 14:49
Just out of curiosity... would using Pycharm be an option for you? You might find it much easier just to use this to set breakpoints — Sayse
– Sayse, Commented Jul 12, 2017 at 14:52
@Sayse I am using charm, but for some reason (probably the huge size of the codebase) using charm's breakpoints and debugger is stupidly slow to run the test. More time wasted, so I tend to just use ipdb. — Aiden Bell
– Aiden Bell, Commented Jul 12, 2017 at 14:56
@MattSeymour thanks for the hint, I will look at pytest-django.readthedocs.io/en/latest — Aiden Bell
– Aiden Bell, Commented Jul 12, 2017 at 14:59

John Moutafis · Accepted Answer · 2017-07-12 15:00:57Z

1

There exist django-nose, a django unittest runner, which still has support for django 1.6 and python 2.7.

There is an --pdb option for nose which:

Drop into debugger on failures or errors

And you can run it as follows:

nosetests --pdb

Since you want to work with ipdb, there exist this nose plugin which allows nose to use ipdb:

nosetests --ipdb

edited Jul 12, 2017 at 15:00

answered Jul 12, 2017 at 14:59

John Moutafis

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3 Comments

Aiden Bell Over a year ago

Looks promising, I will check this out, thanks for the answer +1

John Moutafis Over a year ago

Good luck :) @AidenBell

Aiden Bell Over a year ago

No luck, 1.6 (at least the version we have ... vendored :( ) isn't compatible and working back through the django-nose versions yields no luck. Shame, might plug at it and try to find a workaround as a drop-in looks promising.

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