Add REPORTER and OUTPUT_DIR args to catch_discover_tests

[globberwops]

Description

When using catch_discover_tests with EXTRA_ARGS -o foo, the test reports will be overwritten with each test case.

The args REPORTER, OUTPUT_DIR, OUTPUT_PREFIX, and OUTPUT_SUFFIX will allow for further customization of the test case runs.

• REPORTER can be any valid reporter of the Catch executable.
  The specified reporter will be validated against the available reporters of the Catch executable.
• OUTPUT_DIR can be a relative or an absolute path.
  If relative, it will be relative to the WORKING_DIRECTORY, which in turn defaults to CMAKE_CURRENT_BINARY_DIR.
• OUTPUT_PREFIX is a string that will be added before each test report name.
• OUTPUT_SUFFIX is a string that will be added after each test report name, e.g. a file extension.

GitHub Issues

Resolves #1946

[codecov]

Codecov Report

Merging #2023 into master will decrease coverage by 1.83%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2023      +/-   ##
==========================================
- Coverage   88.75%   86.91%   -1.83%     
==========================================
  Files         138      131       -7     
  Lines        5651     3965    -1686     
==========================================
- Hits         5015     3446    -1569     
+ Misses        636      519     -117     

[horenmar]

A quick note: don't try and enumerate valid reporters up-front, because users might have their own reporters they want to use. It also currently only lists the built-in reporters, but not the ones that Catch2 also provides as part of release (e.g. TAP and TeamCity reporters).

Since you are modifying catch_discover_tests, which already expects to be able to run the test executable, you can instead use --list-reporters and handle its output while validating the argument.

[globberwops]

@horenmar you are totally right, I have added using --list-reporters now. Thanks for the feedback!

[horenmar]

Otherwise LGTM. Can you rebase + squash this into atomic commits?

[horenmar]

Thanks