Adding tests for all PennyLane transforms

[willjmax]

This PR adds unit tests for all PennyLane transforms. This PR addresses [sc-72626].

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.96%. Comparing base (0bcc64c) to head (2ca613b).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1215   +/-   ##
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  Coverage   97.96%   97.96%           
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  Files          77       77           
  Lines       11244    11244           
  Branches      967      967           
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  Hits        11015    11015           
  Misses        180      180           
  Partials       49       49           

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[github-actions]

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[paul0403]

Thanks for adding this, I will take a closer look in a bit, but first @mlxd , what's the guideline on large batches of xfailed python tests like this? Do we prefer skip over xfail, to save CI execution time?

For context, @willjmax is going over the core PL transforms and testing whether qjit works with them or not. If they don't work, a reason is noted in this testing file.