fix broken test by taking into account changed error raised by Python 3.9.7 when copying directory via shutil.copyfile

[boegel]

Fix for failing test for copy_file, due to changes in Python 3.9.7, which is now being used by GitHub Actions to run the tests with Python 3.9

FAIL: test_copy_file (test.framework.filetools.FileToolsTest)
Test copy_file function.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.9.7/x64/lib/python3.9/shutil.py", line 265, in copyfile
    with open(src, 'rb') as fsrc, open(dst, 'wb') as fdst:
IsADirectoryError: [Errno 21] Is a directory: '/tmp/runner/4644539d1162d1bce3b2733a569c795ffd4b1d94/lib/python3.9/site-packages/test/framework/easyconfigs/test_ecs/t/toy'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/tmp/runner/4644539d1162d1bce3b2733a569c795ffd4b1d94/lib/python3.9/site-packages/easybuild/tools/filetools.py", line 2289, in copy_file
    shutil.copy2(path, target_path)
  File "/opt/hostedtoolcache/Python/3.9.7/x64/lib/python3.9/shutil.py", line 443, in copy2
    copyfile(src, dst, follow_symlinks=follow_symlinks)
FileNotFoundError: Directory does not exist: /tmp/eb-uy57tn3z/eb-a541ef4s/eb-kgknsy5e/toy

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/tmp/runner/4644539d1162d1bce3b2733a569c795ffd4b1d94/lib/python3.9/site-packages/easybuild/base/testing.py", line 155, in assertErrorRegex
    call(*args, **kwargs)
  File "/tmp/runner/4644539d1162d1bce3b2733a569c795ffd4b1d94/lib/python3.9/site-packages/easybuild/tools/filetools.py", line 2296, in copy_file
    raise EasyBuildError("Failed to copy file %s to %s: %s", path, target_path, err)
easybuild.tools.build_log.EasyBuildError: 'Failed to copy file /tmp/runner/4644539d1162d1bce3b2733a569c795ffd4b1d94/lib/python3.9/site-packages/test/framework/easyconfigs/test_ecs/t/toy to /tmp/eb-uy57tn3z/eb-a541ef4s/eb-kgknsy5e/toy: Directory does not exist: /tmp/eb-uy57tn3z/eb-a541ef4s/eb-kgknsy5e/toy'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/tmp/runner/4644539d1162d1bce3b2733a569c795ffd4b1d94/lib/python3.9/site-packages/test/framework/filetools.py", line 1613, in test_copy_file
    self.assertErrorRegex(EasyBuildError, "Failed to copy file.*Is a directory", ft.copy_file, src, target)
  File "/tmp/runner/4644539d1162d1bce3b2733a569c795ffd4b1d94/lib/python3.9/site-packages/easybuild/base/testing.py", line 163, in assertErrorRegex
    self.assertTrue(regex.search(msg), "Pattern '%s' is found in '%s'" % (regex.pattern, msg))
AssertionError: None is not true : Pattern 'Failed to copy file.*Is a directory' is found in 'Failed to copy file /tmp/runner/4644539d1162d1bce3b2733a569c795ffd4b1d94/lib/python3.9/site-packages/test/framework/easyconfigs/test_ecs/t/toy to /tmp/eb-uy57tn3z/eb-a541ef4s/eb-kgknsy5e/toy: Directory does not exist: /tmp/eb-uy57tn3z/eb-a541ef4s/eb-kgknsy5e/toy'

From the Python 3.9.7 changelog:

Update shutil.copyfile() to raise FileNotFoundError instead of confusing IsADirectoryError when a path ending with a os.path.sep does not exist; shutil.copy() and shutil.copy2() are also affected.

(see also https://bugs.python.org/issue43219)

[akesandgren]

LGTM

[Flamefire]

FWIW: Upstream issue is https://bugs.python.org/issue43219 not the one from the changelog

[boegel]

FWIW: Upstream issue is https://bugs.python.org/issue43219 not the one from the changelog

But it's the correct one, thanks for pointing that out.