Test fail in some architectures

[sergiopasra]

I'm building a package of pywt for Fedora and running the tests in different architectures.

https://koji.fedoraproject.org/koji/taskinfo?taskID=19794657

One test fails in the following architectures: ppc64le, aarch64, ppc64 and s390x
And passes in x86_64, i686 and armv7hl

For example, this is the build.log in ppc64le
https://kojipkgs.fedoraproject.org//work/tasks/4659/19794659/build.log

The offending test is the following. It's the same failure in Python 2.7

======================================================================
FAIL: test_swt.test_swt_decomposition
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/builddir/build/BUILDROOT/python-pywt-0.5.2-2.fc27.ppc64le/usr/lib64/python3.6/site-packages/pywt/tests/test_swt.py", line 46, in test_swt_decomposition
    assert_allclose(cD3, expected_cD3)
  File "/usr/lib64/python3.6/site-packages/numpy/testing/utils.py", line 1395, in assert_allclose
    verbose=verbose, header=header, equal_nan=equal_nan)
  File "/usr/lib64/python3.6/site-packages/numpy/testing/utils.py", line 778, in assert_array_compare
    raise AssertionError(msg)
AssertionError: 
Not equal to tolerance rtol=1e-07, atol=0
(mismatch 25.0%)
 x: array([ -8.152529e-16,  -3.535534e+00,  -4.242641e+00,  -2.121320e+00,
         7.009625e-16,   3.535534e+00,   4.242641e+00,   2.121320e+00])
 y: array([ 0.      , -3.535534, -4.242641, -2.12132 ,  0.      ,  3.535534,
        4.242641,  2.12132 ])
----------------------------------------------------------------------

[grlee77]

Thanks for reporting this. It looks like the tests just need to allow for a small absolute deviation from the expected result. (i.e. -8.152e-16 is not quite 0). Can you see if the fix proposed in #317 resolves the issue on these architectures?

[sergiopasra]

With this patch, the tests pass in all architectures. Thank you!

[sergiopasra]

https://koji.fedoraproject.org/koji/taskinfo?taskID=19808993 for the record