Bug#951767: python-cartopy test failures with Python 3.8

[Matthias Klose]

Package: src:python-cartopy
Version: 0.17.0+dfsg-8
Severity: serious
Tags: sid bullseye
User: debian-python at lists.debian.org
Usertags: python3.8

Seen with both versions in unstable and experimental, here on amd64:

=================================== FAILURES ===================================
_____________________________ test_transform_point _____________________________

    def test_transform_point():
        """
        Mostly tests the workaround for a specific problem.
        Problem report in: https://github.com/SciTools/cartopy/issues/23
        Fix covered in: https://github.com/SciTools/cartopy/pull/277
        """

        # this way has always worked
        result = _CRS_ROB.transform_point(35.0, 70.0, _CRS_PC)
>       assert_array_almost_equal(result, (2376187.27182751, 7275317.81573085),
                                  _TOL)
E       AssertionError:
E       Arrays are not almost equal to 7 decimals
E
E       Mismatch: 100%
E       Max absolute difference: 0.30056718
E       Max relative difference: 4.13132717e-08
E        x: array([2376187.2182271, 7275318.116298 ])
E        y: array([2376187.2718275, 7275317.8157309])

cartopy/tests/crs/test_robinson.py:126: AssertionError
____________________________ test_transform_points _____________________________

    def test_transform_points():
        """
        Mostly tests the workaround for a specific problem.
        Problem report in: https://github.com/SciTools/cartopy/issues/23
        Fix covered in: https://github.com/SciTools/cartopy/pull/277
        """

        # these always worked
        result = _CRS_ROB.transform_points(_CRS_PC,
                                           np.array([35.0]),
                                           np.array([70.0]))
>       assert_array_almost_equal(result,
                                  [[2376187.27182751, 7275317.81573085, 0]], _TOL)
E       AssertionError:
E       Arrays are not almost equal to 7 decimals
E
E       Mismatch: 66.7%
E       Max absolute difference: 0.30056718
E       Max relative difference: 4.13132717e-08
E        x: array([[2376187.2182271, 7275318.116298 ,       0.       ]])
E        y: array([[2376187.2718275, 7275317.8157309,       0.       ]])

cartopy/tests/crs/test_robinson.py:149: AssertionError
== 2 failed, 421 passed, 2 skipped, 111 deselected, 2 xfailed in 8.37 seconds ==
E: pybuild pybuild:341: test: plugin distutils failed with: exit code=1: cd
'/packages/tmp/p/python-cartopy-0.18.0~b1+dfsg/.pybuild/cpython3_3.8_cartopy/build';
python3.8 -m pytest --pyargs -m "not network and not natural_earth"