Measure test coverage as part of CI runs

[edwardhartnett]

We need to somehow measure and display test coverage as part of CI.

[kgerheiser]

I was able to do this in Github by installing gcovr and passing CMAKE_Fortran_FLAGS for the necessary flags through the command line.

The issue is outputting the data. With Github Actions you can save artifacts as a .zip, but that's it. There's no way to directly view the HTML output. You have to manually download it to look at the results.

There's https://about.codecov.io which is a service that does this and integrates into Github, but it requires paying for it.

So, my plan is to upload the .html files and you'll have to manually look at them.

[edwardhartnett]

OK, that works for now, and maybe we can improve it later...

[kgerheiser]

Fixed with #380

@edwardhartnett there's this issue in the upload artifact Action to be able to view files in the browser, and hopefully it's coming. actions/upload-artifact#14

[edwardhartnett]

OK, in the meantime, what's the procedure for getting the package of html files?

[kgerheiser]

You go to Actions, click on a workflow run, and it's listed on the bottom under Artifacts as test-coverage. Click on that and it downloads.

See here, for example:

https://github.com/NOAA-EMC/UFS_UTILS/actions/runs/618295926

[edwardhartnett]

When I upload this and unzip, there is just one file, the main report file. But there should be a bunch more HTML files, one for each code file as well...

[kgerheiser]

I was using the option --html which outputs just a single HTML file. The command --html-details makes a page for each file.