Added new DL_PATHS option to catch_discover_tests()

[mheimlich]

Description

This enables setting required PATH/LD_LIBRARY_PATH environment variables both when retrieving the list of test cases and when executing the tests.

Some test executables depend on shared libraries and thus can only be launched when the dynamic linker can find their dependencies. With set_tests_properties() it is possible to extend PATH/LD_LIBRARY_PATH with the ENVIRONMENT property of a test. Unfortunately this does not work with the PROPERTIES parameter of catch_discover_tests() (especially on Windows because of the ; seperator).

At first I tried integrating this by parsing said ENVIRONMENT property but ultimately failed due to both my and the cmake language limitations. So I implemented this as a new parameter, which makes it easier to handle the list of paths.

I did not find any existing tests for catch_discover_tests(), so I did not extend/add one for this. If there is one, please point me in the right direction and I'll add one.

[codecov]

Codecov Report

Merging #2467 (3828106) into devel (8730260) will not change coverage.
The diff coverage is n/a.

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  Coverage   91.49%   91.49%           
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  Lines        7519     7519           
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  Hits         6879     6879           
  Misses        640      640           

[horenmar]

There aren't any tests for catch_discover_tests. If someone wanted to add them I would merge them, but adding them is very low on my own priority list.

[horenmar]

Thanks, this looks reasonable enough.

[mchapman87501]

Thanks for adding DL_PATHS!
Unfortunately, I'm having trouble getting it to work on macOS. When running on macOS, I believe CatchAddTests.cmake needs to set DYLD_LIBRARY_PATH instead of LD_LIBRARY_PATH.

[mheimlich]

@mchapman87501 I have adapted it to use DYLD_LIBRARY_PATH on Apple plaftorms in https://github.com/mheimlich/Catch2/tree/catch_discover_macos
Please test if this works for you, then I'll open a pull request here.

[mchapman87501]

This works. Thank you!

I've attached a small project to demonstrate the problem and to show that the fix works.
Apologies in advance: it's fragile. Among other things it uses homebrew's Catch2 -- whatever version is current as of today -- to demonstrate the failure case.

demo_catch2_dl_path.zip