Error with apps_base.py

[aturner-epcc]

When trying to port tests to Cirrus EX, I consistantly get the following error from ReFrame:

WARNING: skipping test file 'epcc-reframe/tests/apps/apps_base.py': type error: metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases:
| /mnt/lustre/e1000/home/z04/z04/aturner/test/cirrus-ex/reframe/epcc-reframe/tests/apps/apps_base.py:29
| class AppsCompileBase(rfm.CompileOnlyRegressionTest, metaclass=abc.ABCMeta):

rerun with '-v' for a backtrace
Traceback (most recent call last):
  File "/work/y07/shared/cirrus-ex/cirrus-ex-software/utils/core/reframe/4.8.4/reframe/frontend/loader.py", line 219, in load_from_file
    util.import_module_from_file(filename, force,
  File "/work/y07/shared/cirrus-ex/cirrus-ex-software/utils/core/reframe/4.8.4/reframe/utility/__init__.py", line 118, in import_module_from_file
    return _do_import_module_from_file(filename, module_name)
  File "/work/y07/shared/cirrus-ex/cirrus-ex-software/utils/core/reframe/4.8.4/reframe/utility/__init__.py", line 70, in _do_import_module_from_file
    spec.loader.exec_module(module)
  File "<frozen importlib._bootstrap_external>", line 850, in exec_module
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
  File "/mnt/lustre/e1000/home/z04/z04/aturner/test/cirrus-ex/reframe/epcc-reframe/tests/apps/apps_base.py", line 29, in <module>
    class AppsCompileBase(rfm.CompileOnlyRegressionTest, metaclass=abc.ABCMeta):
TypeError: metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases

[lucaparisi91]

Which reframe and python version are you using ?

[eleanor-broadway]

This apps_base is not being used for any in-production tests at the moment. It was written by @JPRichings to contain some example code and as kind of a vision for the future if we could prevent duplication across different app tests.

I edited it so it passed the linting tests and decided to keep it in as an example, but in reality all of our existing tests have their own base. So, if it is a conflict it can be removed!