Test failures on Python 3.10

[fabaff]

With Python 3.10 some tests are failing.

============================= test session starts ==============================
platform linux -- Python 3.10.1, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: /build/apptools-5.1.0
collected 277 items / 3 errors / 274 selected                                  

==================================== ERRORS ====================================
___________ ERROR collecting apptools/io/h5/tests/test_dict_node.py ____________
ImportError while importing test module '/build/apptools-5.1.0/apptools/io/h5/tests/test_dict_node.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/nix/store/b798fp24zf2fdafmyyc4sxfr48ly5yy9-python3-3.10.1/lib/python3.10/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
apptools/io/h5/tests/test_dict_node.py:21: in <module>
    from .utils import open_h5file, temp_h5_file, temp_file
apptools/io/h5/tests/utils.py:14: in <module>
    from ..utils import open_h5file
apptools/io/h5/utils.py:12: in <module>
    from .file import H5File
apptools/io/h5/file.py:10: in <module>
    from collections import Mapping, MutableMapping
E   ImportError: cannot import name 'Mapping' from 'collections' (/nix/store/b798fp24zf2fdafmyyc4sxfr48ly5yy9-python3-3.10.1/lib/python3.10/collections/__init__.py)
______________ ERROR collecting apptools/io/h5/tests/test_file.py ______________
ImportError while importing test module '/build/apptools-5.1.0/apptools/io/h5/tests/test_file.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/nix/store/b798fp24zf2fdafmyyc4sxfr48ly5yy9-python3-3.10.1/lib/python3.10/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
apptools/io/h5/tests/test_file.py:22: in <module>
    from ..file import H5File
apptools/io/h5/file.py:10: in <module>
    from collections import Mapping, MutableMapping
E   ImportError: cannot import name 'Mapping' from 'collections' (/nix/store/b798fp24zf2fdafmyyc4sxfr48ly5yy9-python3-3.10.1/lib/python3.10/collections/__init__.py)
___________ ERROR collecting apptools/io/h5/tests/test_table_node.py ___________
ImportError while importing test module '/build/apptools-5.1.0/apptools/io/h5/tests/test_table_node.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/nix/store/b798fp24zf2fdafmyyc4sxfr48ly5yy9-python3-3.10.1/lib/python3.10/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
apptools/io/h5/tests/test_table_node.py:23: in <module>
    from .utils import temp_h5_file
apptools/io/h5/tests/utils.py:14: in <module>
    from ..utils import open_h5file
apptools/io/h5/utils.py:12: in <module>
    from .file import H5File
apptools/io/h5/file.py:10: in <module>
    from collections import Mapping, MutableMapping
E   ImportError: cannot import name 'Mapping' from 'collections' (/nix/store/b798fp24zf2fdafmyyc4sxfr48ly5yy9-python3-3.10.1/lib/python3.10/collections/__init__.py)
=============================== warnings summary ===============================

At first glance it seems that the issue is related to the changes in the collections interface starting with Python 3.10.

[susnux]

Can be fixed with a simple patch (should also work with previous python versions):

diff -Nur apptools-5.1.0/apptools/io/h5/file.py new/apptools/io/h5/file.py
--- apptools-5.1.0/apptools/io/h5/file.py	2021-01-13 20:10:47.000000000 +0100
+++ new/apptools/io/h5/file.py	2022-05-02 22:42:46.404485964 +0200
@@ -7,7 +7,7 @@
 # is also available online at http://www.enthought.com/licenses/BSD.txt
 #
 # Thanks for using Enthought open source!
-from collections import Mapping, MutableMapping
+from collections.abc import Mapping, MutableMapping
 from functools import partial
 import inspect