TestTopdirTrash.test_trash test fails on macOS

[nieder]

On macOS, TestTopdirTrash.test_trash from v1.5.0 fails like this for pythons 27, 34-37.

$ PYTHONPATH=/sw/build.build/send2trash-py27-1.5.0-1/Send2Trash-1.5.0/build/lib /sw/bin/pytest-2.7 -v
======================================== test session starts =========================================
platform darwin -- Python 2.7.16, pytest-3.10.1, py-1.7.0, pluggy-0.7.1 -- /sw/bin/python2.7
cachedir: .pytest_cache
rootdir: /sw/build.build/send2trash-py27-1.5.0-1/Send2Trash-1.5.0, inifile:
plugins: mock-1.10.0
collected 9 items                                                                                    

tests/test_plat_other.py::TestHomeTrash::test_trash PASSED                                     [ 11%]
tests/test_plat_other.py::TestUnicodeTrash::test_trash_bytes PASSED                            [ 22%]
tests/test_plat_other.py::TestUnicodeTrash::test_trash_unicode PASSED                          [ 33%]
tests/test_plat_other.py::TestTopdirTrash::test_trash FAILED                                   [ 44%]
tests/test_plat_other.py::TestTopdirTrashFallback::test_trash PASSED                           [ 55%]
tests/test_plat_other.py::TestTopdirFailure::test_trash PASSED                                 [ 66%]
tests/test_plat_other.py::TestSymlink::test_trash PASSED                                       [ 77%]
tests/test_plat_win.py::TestLongPath::test_trash_file SKIPPED                                  [ 88%]
tests/test_plat_win.py::TestLongPath::test_trash_folder SKIPPED                                [100%]

============================================== FAILURES ==============================================
_____________________________________ TestTopdirTrash.test_trash _____________________________________

self = <tests.test_plat_other.TestTopdirTrash testMethod=test_trash>

    def test_trash(self):
        s2t(self.filePath)
        self.assertFalse(op.exists(self.filePath))
>       self.assertTrue(op.exists(op.join(self.trashDir, str(os.getuid()), 'files', self.fileName)))
E       AssertionError: False is not true

tests/test_plat_other.py:115: AssertionError
=========================== 1 failed, 6 passed, 2 skipped in 0.09 seconds ============================

@dhomeier

[denini08]

Hi! I was browsing through the project issues and noticed this one about portability.

I went ahead and created this fix to help out.

Happy to contribute to the project!

Let me know if you need any changes or have feedback on the approach.