Pytest fails on windows

[vinferrer]

Hello there,

I was trying the cirrus-ci config and realised that there is a fail in the tests in windows:

============================= test session starts =============================
platform win32 -- Python 3.8.5, pytest-6.2.2, py-1.10.0, pluggy-0.13.1
rootdir: C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build, configfile: setup.cfg
plugins: cov-2.11.1
collected 20 items
peakdet\tests\test_analytics.py .                                        [  5%]
peakdet\tests\test_editor.py .                                           [ 10%]
peakdet\tests\test_external.py F                                         [ 15%]
peakdet\tests\test_io.py ....                                            [ 35%]
peakdet\tests\test_operations.py .......                                 [ 70%]
peakdet\tests\test_physio.py ..                                          [ 80%]
peakdet\tests\test_utils.py ....                                         [100%]WARNING: Failed to generate report: No data to report.
================================== FAILURES ===================================
______________________________ test_load_rtpeaks ______________________________
    def test_load_rtpeaks():
        for channel in [1, 2, 9]:
            with pytest.warns(UserWarning):
                hist = dict(fname=DATA, channel=channel, fs=1000.)
                phys = external.load_rtpeaks(DATA, channel=channel, fs=1000.)
                assert phys.history == [('load_rtpeaks', hist)]
                assert phys.fs == 1000.
                with pytest.raises(ValueError):
>                   external.load_rtpeaks(testutils.get_test_data_path('ECG.csv'),
                                          channel=channel, fs=1000.)
E                   Failed: DID NOT WARN. No warnings of type (<class 'UserWarning'>,) was emitted. The list of emitted warnings is: [].
peakdet\tests\test_external.py:18: Failed
----------- coverage: platform win32, python 3.8.5-final-0 -----------
======================== 1 failed, 19 passed in 18.55s ========================

I added an xfail to avoid this error for the moment but it should be addressed if you wanna support windows. @smoia told me that maybe @rmarkello could know the solution