Steven D'Aprano added the comment: On 15/08/13 22:58, ezio.melo...@gmail.com wrote: > http://bugs.python.org/review/18606/diff/8927/Lib/statistics.py#newcode277 > Lib/statistics.py:277: assert isinstance(x, float) and > isinstance(partials, list) > Is this a good idea?
I think so add_partials is internal/private, and so I don't have to worry about the caller providing wrong arguments, say a non-float. But I want some testing to detect coding errors. Using assert for this sort of internal pre-condition is exactly what assert is designed for. > http://bugs.python.org/review/18606/diff/8927/Lib/test/test_statistics.py#newcode144 > Lib/test/test_statistics.py:144: assert data != sorted(data) > Why not assertNotEqual? I use bare asserts for testing code logic, even if the code is test code. So if I use self.assertSpam(...) then I'm performing a unit test of the module being tested. If I use a bare assert, I'm asserting something about the test logic itself. > http://bugs.python.org/review/18606/diff/8927/Lib/test/test_statistics_approx.py > File Lib/test/test_statistics_approx.py (right): > > http://bugs.python.org/review/18606/diff/8927/Lib/test/test_statistics_approx.py#newcode1 > Lib/test/test_statistics_approx.py:1: """Numeric approximated equal > comparisons and unit testing. > Do I understand correctly that this is just an helper module used in > test_statistics and that it doesn't actually test anything from the > statistics module? Correct. > http://bugs.python.org/review/18606/diff/8927/Lib/test/test_statistics_approx.py#newcode137 > Lib/test/test_statistics_approx.py:137: # and avoid using > TestCase.almost_equal, because it sucks > Could you elaborate on this? Ah, I misspelled "TestCase.AlmostEqual". - Using round() to test for equal-to-some-tolerance is IMO quite an idiosyncratic way of doing approx-equality tests. I've never seen anyone do it that way before. It surprises me. - It's easy to think that ``places`` means significant figures, not decimal places. - There's now a delta argument that is the same as my absolute error tolerance ``tol``, but no relative error argument. - You can't set a per-instance error tolerance. > http://bugs.python.org/review/18606/diff/8927/Lib/test/test_statistics_approx.py#newcode241 > Lib/test/test_statistics_approx.py:241: assert len(args1) == len(args2) > Why not assertEqual? As above, I use bare asserts to test the test logic, and assertSpam methods to perform the test. In this case, I'm confirming that I haven't created dodgy test data. > http://bugs.python.org/review/18606/diff/8927/Lib/test/test_statistics_approx.py#newcode255 > Lib/test/test_statistics_approx.py:255: self.assertTrue(approx_equal(b, > a, tol=0, rel=rel)) > Why not assertApproxEqual? Because I'm testing the approx_equal function. I can't use assertApproxEqual to test its own internals. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue18606> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
