Why cProfile module doesn't work with unittest?

You have to initialize the cProfiler in the Constructor of the test, and use the profile data in destructor -- I use it like that:

from pstats import Statsimport unittestclass TestSplayTree(unittest.TestCase):    """a simple test"""    def setUp(self):        """init each test"""        self.testtree = SplayTree (1000000)        self.pr = cProfile.Profile()        self.pr.enable()        print "\n<<<---"    def tearDown(self):        """finish any test"""        p = Stats (self.pr)        p.strip_dirs()        p.sort_stats ('cumtime')        p.print_stats ()        print "\n--->>>"    def xtest1 (self):        pass

In case that a test waits for input, one needs to call self.pr.disable() before that call, and re-enable it afterwards.

If you prefer pytest the method names are a bit different:

import cProfileimport timeclass TestProfile:    """ test to illustrate cProfile usage """    def setup_class(self):        self.pr = cProfile.Profile()        self.pr.enable()    def teardown_class(self):        self.pr.disable()        self.pr.print_stats(sort="tottime")    def test_sleep(self):        time.sleep(2)

Specifying the module explicitly fixed this for me. That is, replacing...

    unittest.main()

...(which tried to auto-discover what tests it should be running) with...

    unittest.main(module='mytest')  # if in 'mytest.py', or as appropriate for your filename/module

...allowed proper profiling as python -m cProfile mytest.py.

I'm not sure why, but explicitly creating and running a test suite seems to work. I added time.sleep(2) to show something definitive in the stats.

import timeimport unittestclass TestBasic(unittest.TestCase):    def testFoo(self):        time.sleep(2)        assert True == Trueif __name__ == '__main__':    suite = unittest.TestLoader().loadTestsFromTestCase(TestBasic)    unittest.TextTestRunner(verbosity=2).run(suite)

Running in bash, only keeping the first 10 lines, we can see {time.sleep} was the longest running call:

~ $ python -m cProfile -s tottime so.py | head -n10testFoo (__main__.TestBasic) ... ok----------------------------------------------------------------------Ran 1 test in 2.003sOK         1084 function calls (1072 primitive calls) in 2.015 seconds   Ordered by: internal time   ncalls  tottime  percall  cumtime  percall filename:lineno(function)        1    2.003    2.003    2.003    2.003 {time.sleep}        1    0.002    0.002    0.003    0.003 case.py:1(<module>)        1    0.002    0.002    0.003    0.003 collections.py:11(<module>)        1    0.001    0.001    2.015    2.015 so.py:1(<module>)        1    0.001    0.001    0.010    0.010 __init__.py:45(<module>)