[Numpy-discussion] Odd nosetest error in test_umath.py

[Charles R Harris]

On Thu, Jul 23, 2009 at 4:56 PM, Matthew Brett <matthew.brett@gmail.com>wrote:

> Hi,
>
> I just got an email about a broken buildbot build.  Looking at the
> logs, I see this:
>
> ======================================================================
> FAIL: Test bug in reduceat with structured arrays copied for speed.
> ----------------------------------------------------------------------
> Traceback (most recent call last):
>  File "/var/lib/python-support/python2.5/nose/case.py", line 182, in
> runTest
>    self.test(*self.arg)
>  File
> "/home/numpybb/Buildbot/numpy/b14/numpy-install/lib/python2.5/site-packages/numpy/core/tests/test_umath.py",
> line 818, in test_reduceat
>    assert_array_almost_equal(h1, h2)
>  File
> "../numpy-install/lib/python2.5/site-packages/numpy/testing/utils.py",
> line 537, in assert_array_almost_equal
>  File
> "../numpy-install/lib/python2.5/site-packages/numpy/testing/utils.py",
> line 395, in assert_array_compare
> AssertionError:
> Arrays are not almost equal
>
> (mismatch 100.0%)
>  x: array([  701.1171875,   801.1171875,  1001.1171875,
> 7501.1171875], dtype=float32)
>  y: array([  700.,   800.,  1000.,  7500.], dtype=float32)
>
> I'm posting because I saw this bug before on one of my own machines.
> It is an extremely strange error that  seemed to occur in the
> following circumstances:
>
> 1) Running via nosetests
> 2) With one or more other tests in the same file as the test above,
> where the test was a TestCase class
> 3) With nose 0.10.3, 0.10.4, but not 0.11
>
> The error given seemed to be reliable, but differed in the numbers
> given for different versions of the test file (but stayed the same for
> any given version when the test was repeated)
>
> Consider this example on my own machine:
>
> mb312@fedora11:~$ nosetests sp/numpy/core/tests/test_umath.py
> ...
> (mismatch 100.0%)
>  x: array([  800.,   900.,  1100.,  7600.], dtype=float32)
>  y: array([  700.,   800.,  1000.,  7500.], dtype=float32)
>
> ----------------------------------------------------------------------
> Ran 71 tests in 0.064s
>
> FAILED (errors=1, failures=1)
>
> (where the error is a SkipTest).
>
> Now, just running the failing test via nose:
>
> mb312@fedora11:~$ nosetests
> sp/numpy/core/tests/test_umath.py:test_reduceat
> .
> ----------------------------------------------------------------------
> Ran 1 test in 0.001s
>
> OK
>

It's been there ever since Travis added the test, but it is sporadic. It's
probably a reference counting error somewhere but no one has tracked it down
yet. There is a ticket open on it.

Chuck
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