test_rank_filter can fail

[hmaarrfk]

Description

============== FAILURES ===================================

________________ TestRank.test_rank_filter[windowed_histogram] _________________

self = <skimage.filters.rank.tests.test_rank.TestRank object at 0x10c856580>

filter = 'windowed_histogram'

    @parametrize('filter', all_rank_filters)

    def test_rank_filter(self, filter):

        @test_parallel(warnings_matching=['Possible precision loss'])

        def check():

            expected = self.refs[filter]

            result = getattr(rank, filter)(self.image, self.selem)

            if filter == "entropy":

                # There may be some arch dependent rounding errors

                # See the discussions in

                # https://github.com/scikit-image/scikit-image/issues/3091

                # https://github.com/scikit-image/scikit-image/issues/2528

                assert_allclose(expected, result, atol=0, rtol=1E-15)

            elif filter == "otsu":

                # OTSU May also have some optimization dependent failures

                # See the discussions in

                # https://github.com/scikit-image/scikit-image/issues/3091

                # Pixel 3, 5 was found to be problematic. It can take either

                # a value of 41 or 81 depending on the specific optimizations

                # used.

                assert result[3, 5] in [41, 81]

                result[3, 5] = 81

                # Pixel [19, 18] is also found to be problematic for the same

                # reason.

                assert result[19, 18] in [141, 172]

                result[19, 18] = 172

                assert_array_equal(expected, result)

            else:

                assert_array_equal(expected, result)

    

>       check()

../../venv/lib/python3.8/site-packages/skimage/filters/rank/tests/test_rank.py:86: 

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

../../venv/lib/python3.8/site-packages/skimage/_shared/testing.py:246: in inner

    result = func(*args, **kwargs)

../../venv/lib/python3.8/site-packages/skimage/filters/rank/tests/test_rank.py:61: in check

    expected = self.refs[filter]

../../venv/lib/python3.8/site-packages/numpy/lib/npyio.py:260: in __getitem__

    return format.read_array(bytes,

../../venv/lib/python3.8/site-packages/numpy/lib/format.py:710: in read_array

    version = read_magic(fp)

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

fp = <zipfile.ZipExtFile name='windowed_histogram.npy' mode='r'>

    def read_magic(fp):

        """ Read the magic string to get the version of the file format.

    

        Parameters

        ----------

        fp : filelike object

    

        Returns

        -------

        major : int

        minor : int

        """

        magic_str = _read_bytes(fp, MAGIC_LEN, "magic string")

        if magic_str[:-2] != MAGIC_PREFIX:

            msg = "the magic string is not correct; expected %r, got %r"

>           raise ValueError(msg % (MAGIC_PREFIX, magic_str[:-2]))

E           ValueError: the magic string is not correct; expected b'\x93NUMPY', got b'\x00\x00\x00\x00\x00\x00'

https://travis-ci.org/scikit-image/scikit-image/jobs/624812341?utm_medium=notification&utm_source=github_status

Way to reproduce

# Place the full code we need to recreate your issue here
# upload all necessary images to github too!

Version information

# Paste the output of the following python commands
from __future__ import print_function
import sys; print(sys.version)
import platform; print(platform.platform())
import skimage; print("scikit-image version: {}".format(skimage.__version__))
import numpy; print("numpy version: {}".format(numpy.__version__))

# your output here

[grlee77]

Closed by #5175