two analysis/test_encore.py tests failing on Fedora 29 (rawhide)

[rathann]

Expected behaviour

All tests pass.

Actual behaviour

TestEncore.test_hes_to_self and TestEncore.test_hes_custom_weights fail in Fedora 29 (rawhide) build environment on x86_64. Versions of installed dependencies (some have fc28 because they haven't been rebuilt since Fedora 28):

python2-Cython-0.28.1-1.fc29.x86_64
python2-GridDataFormats-0.4.0-1.fc28.noarch
python2-biopython-1.71-2.fc29.x86_64
python2-devel-2.7.15-2.fc29.x86_64
python2-gsd-1.5.1-1.fc29.x86_64
python2-hypothesis-3.49.0-1.fc29.noarch
python2-joblib-0.11-4.fc29.noarch
python2-matplotlib-2.1.2-2.fc28.x86_64
python2-mmtf-1.1.2-1.fc29.noarch
python2-mock-2.0.0-8.fc29.noarch
python2-netcdf4-1.2.9-5.fc29.x86_64
python2-networkx-1.11-11.fc29.noarch
python2-numpy-1.14.5-1.fc29.x86_64
python2-psutil-5.4.3-4.fc28.x86_64
python2-pytest-xdist-1.22.2-1.fc29.noarch
python2-scikit-learn-0.19.1-2.fc28.x86_64
python2-setuptools-39.2.0-1.fc29.noarch
python2-tempdir-0.7.1-6.fc28.noarch

Code to reproduce the behaviour

$ PYTHONPATH=/builddir/build/BUILDROOT/python-MDAnalysis-0.18.0-1.fc29.x86_64/usr/lib64/python2.7/site-packages:/builddir/build/BUILDROOT/python-MDAnalysis-0.18.0-1.fc29.x86_64/usr/lib/python2.7/site-packages pytest-2 analysis/test_encore.py
================================================= test session starts ==================================================
platform linux2 -- Python 2.7.15, pytest-3.6.2, py-1.5.4, pluggy-0.6.0
rootdir: /builddir/build/BUILD/MDAnalysis-0.18.0/MDAnalysisTests-0.18.0, inifile: setup.cfg
plugins: xdist-1.22.2, forked-0.2, hypothesis-3.49.0
collected 46 items                                                                                                     

analysis/test_encore.py .......F.F....................................                                           [100%]

======================================================= FAILURES =======================================================
_____________________________________________ TestEncore.test_hes_to_self ______________________________________________

self = <MDAnalysisTests.analysis.test_encore.TestEncore object at 0x7f593a1fc250>, ens1 = <Universe with 3341 atoms>

    def test_hes_to_self(self, ens1):
        results, details = encore.hes([ens1, ens1])
        result_value = results[0, 1]
        expected_value = 0.
        assert_almost_equal(result_value, expected_value,
>                           err_msg="Harmonic Ensemble Similarity to itself not zero: {0:f}".format(result_value))
E       AssertionError: 
E       Arrays are not almost equal to 7 decimals
E       Harmonic Ensemble Similarity to itself not zero: -0.054989
E        ACTUAL: -0.05498861726156967
E        DESIRED: 0.0

analysis/test_encore.py:232: AssertionError
__________________________________________ TestEncore.test_hes_custom_weights __________________________________________

self = <MDAnalysisTests.analysis.test_encore.TestEncore object at 0x7f593351dad0>, ens1 = <Universe with 3341 atoms>
ens2 = <Universe with 3341 atoms>

    def test_hes_custom_weights(self, ens1, ens2):
        results, details = encore.hes([ens1, ens2], weights='mass')
        results_custom, details_custom = encore.hes([ens1, ens2],
                                                    weights=(ens1.select_atoms('name CA').masses,
                                                             ens2.select_atoms('name CA').masses))
        result_value = results[0, 1]
        result_value_custom = results_custom[0, 1]
>       assert_almost_equal(result_value, result_value_custom)
E       AssertionError: 
E       Arrays are not almost equal to 7 decimals
E        ACTUAL: 6472928.4152650405
E        DESIRED: 6513372.287219666

analysis/test_encore.py:248: AssertionError
========================================= 2 failed, 44 passed in 35.22 seconds =========================================

Currently version of MDAnalysis:

0.18.0

[orbeckst]

This issue and #35 are related. See discussion on #35.