Fix mock_run_vasp to accept args and test docs

[mjwen]

This PR introduces two fixes related to the test system.

• Fix mock_run_vasp to accept *args and **kwargs to match the signature of run_vasp. Otherwise, if a job maker sets some of these arguments (for example, the coming MD maker will set handler), the test will fail.

• Fix doc on writing tests: changing the unit cell of the Si structure to avoid failing check_poscar. In check_poscar, the user poscar will use a lattice of

  3.348898 0.000000 1.933487
  1.116299 3.157372 1.933487
  0.000000 0.000000 3.866975
  

  while the ref poscar will use whatever lattice provided in the test file. The current doc on test suggests to use

0.000000 2.730000 2.730000
2.730000 0.000000 2.730000
2.730000 2.730000 0.000000

A test will fail if the two do not match. Currently, I just update the doc to make the the same. But I believe there should be better ways to do it. For example, what if a new maker do not want to use Si as the test system? Basically, it seems the user poscar is hard-coded? I know it is copied from somewhere to a tmpdir (cwd), but I don't know where the copy happens.

Additional dependencies introduced (if any)

None

TODO (if any)

None

Checklist

Work-in-progress pull requests are encouraged, but please put [WIP] in the pull request
title.

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• [NA] Docstrings have been added in theNumpy docstring format.
  Run pydocstyle on your code.
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• [NA] Tests have been added for any new functionality or bug fixes.
• All linting and tests pass.

[codecov]

Codecov Report

Merging #151 (9be35b1) into main (f238e11) will not change coverage.
The diff coverage is n/a.

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  Misses        973      973           
  Partials      169      169           

[utf]

Thanks!