[Python-modules-team] Bug#967977: scipy: Test failures silently ignored during build

[Christian Kastner]

Source: scipy
Version: 1.5.2-2
Severity: important

With the recent 1.5.2-2, src: scikit-learn FTBFS on s390x because of a
failed unit test.

The unit test uses scipy.stats.gaussian_kde, whose evaluate() method
returns all zeros in the tested cases.

scipy's own test suite reports the same error during build [1], however
the failed tests seem to be silently ignored. For example:

> ../../debian/python3-scipy/usr/lib/python3.8/dist-packages/scipy/stats/tests/test_kdeoth.py:316: in test_kde_integer_input
>     assert_array_almost_equal(kde(x1), y_expected, decimal=6)
> E   AssertionError: 
> E   Arrays are not almost equal to 6 decimals
> E   
> E   Mismatched elements: 5 / 5 (100%)
> E   Max absolute difference: 0.19514935
> E   Max relative difference: 1.
> E    x: array([0., 0., 0., 0., 0.])
> E    y: array([0.134807, 0.182229, 0.195149, 0.182229, 0.134807])

Note the 'x' being all zeros, which is what I'm observing with
scikit-learn.

[1] https://buildd.debian.org/status/fetch.php?pkg=scipy&arch=s390x&ver=1.5.2-2&stamp=1596264715&raw=0