Issue #326: Add new regex to catch MUMmer v4 version information

[baileythegreen]

Adds new code to catch version information for new version of MUMmer.

Feedback may be needed on the specific error types used.

Note: this will likely require some new tests (to-be-written).

Closes #326.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality not to work as expected)
• This change requires a documentation update
• This is a documentation update

Action Checklist

• Work on a single issue/concept (if there are multiple separate issues to address, please use a separate pull request for each)
• Fork the pyani repository under your own account (please allow write access for repository maintainers)
• Set up an appropriate development environment (please see CONTRIBUTING.md)
• Create a new branch with a short, descriptive name
• Work on this branch
  • style guidelines have been followed
  • new code is commented, especially in hard-to-understand areas
  • corresponding changes to documentation have been made
  • tests for the change have been added that demonstrate the fix or feature works
• Test locally with pytest -v non-passing code will not be merged
• Rebase against origin/master
• Check changes with flake8 and black before submission
• Commit branch
• Submit pull request, describing the content and intent of the pull request
• Request a code review
• Continue the discussion at Pull requests section in the pyani repository

[codecov]

Codecov Report

Merging #335 (62967a0) into master (c0fdf6d) will increase coverage by 0.15%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #335      +/-   ##
==========================================
+ Coverage   76.32%   76.47%   +0.15%     
==========================================
  Files          52       52              
  Lines        3404     3414      +10     
==========================================
+ Hits         2598     2611      +13     
+ Misses        806      803       -3     

[widdowquinn]

One small note at l.140. (also make Exception catching specific for PermissionError and FileNotFoundError when can't find exacutable - do we need to do this for the other tools, also?)

[baileythegreen]

Re: the PermissionError check we discussed adding, I think this may actually be superfluous: if not os.access(nucmer_path, os.X_OK) checks whether the file is executable; from looking into it, I don't think this command would return True, unless the individual had execute permissions on the file.

The other options for os.access()'s second argument check whether the user has read or write permissions for the file.