Why cProfile module doesn't work with unittest?

Question

I would to use cProfile module to profile my unit tests. But when I run

python -mcProfile mytest.py

I got 'Ran 0 tests in 0.000s'. Here is the source code of mytest.py

import unittest

class TestBasic(unittest.TestCase):
    def testFoo(self):
        assert True == True

if __name__ == '__main__':
    unittest.main()

I've tested with other more complex unittests as well. Always got 'Ran 0 tests' if I run it with cProfile. Please help.

UPDATE: My OS is MacOS 10.7 with built-in python 2.7. The same code works properly on ubuntu.

works for me under Ubuntu - python2.6/2.7 :) Did you try with the `Profile` module only ? — Cédric Julien, Jul 25 '12 at 08:14
Thanks, Julien. Just tested on ubuntu and it works. Looks like its a platform specific issue. It doesn't work on MacOS 10.7 with built-in python 2.7. — Ryan Ye, Jul 25 '12 at 09:24
I realize that this question is kind of old, but it does not seem to be specific to OS X after all: I can reproduce the problem in the question with Ubuntu 13.04 and Python 2.7.4. Unfortunately, I don't have an answer either. — rainer, Aug 06 '13 at 13:49

score 17 · Answer 1 · edited Dec 04 '19 at 10:45

17

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 Stats
import unittest

class 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 cProfile
import time

class 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)

edited Dec 04 '19 at 10:45

Roelant

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answered Nov 27 '13 at 19:29

alinsoar

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Still didn't work for me when I wanted to use flask test clients. – Michel Müller Apr 08 '14 at 12:20
3

FYI, the Stats class is available via `from pstats import Stats` – Chris Betti Jun 12 '15 at 17:37
1

Is `self.testtree = SplayTree (1000000)` essential here? – industryworker3595112 Oct 15 '15 at 06:04
I copied and pasted from my implementation of splay trees, very old. I did it about 3 years ago I think. Anyway, my implementation works well. If you really need, I may open the archives and see. – alinsoar Nov 07 '15 at 21:59
2

No need for `self.testtree = SplayTree (1000000)`. Or you need to provide import for it – Bostone Nov 30 '17 at 17:42
This doesnt answer the question, which asked why it doesnt work from the command line – ByteMe95 May 10 '22 at 20:25

score 12 · Answer 2 · answered May 15 '20 at 21:30

12

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.

answered May 15 '20 at 21:30

gojomo

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1

Just as as explanation of this idea: By default, unittest.main() looks for unit TestCase objects in the '__main__' module. So when we run it over cProfile module name is differ, and when we define explicit name in unittest.main(module='mytest') it works – Andrii Danyleiko Nov 08 '20 at 22:56
4

works, and by far the least intrusive and complicated of the answers. – JL Peyret Apr 14 '21 at 15:57

Zach Young · Answer 3 · 2019-03-15T05:42:16.373

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 time
import unittest

class TestBasic(unittest.TestCase):
    def testFoo(self):
        time.sleep(2)
        assert True == True

if __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 -n10
testFoo (__main__.TestBasic) ... ok

----------------------------------------------------------------------
Ran 1 test in 2.003s

OK
         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>)

Why cProfile module doesn't work with unittest?

3 Answers3