Add Fortran interface tests

[benegee]

Resolves #82

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: +2.38% 🎉

Comparison is base (c75552d) 95.81% compared to head (c1f5b43) 98.20%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #89      +/-   ##
==========================================
+ Coverage   95.81%   98.20%   +2.38%     
==========================================
  Files          12       12              
  Lines         502      500       -2     
==========================================
+ Hits          481      491      +10     
+ Misses         21        9      -12     

Flag	Coverage Δ
unittests	98.20% <ø> (+2.38%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
src/api.c	100.00% <ø> (+4.39%)	⬆️

... and 1 file with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[benegee]

Finally!

Coverage is looking good as well. New "issues":

void trixi_initialize(const char * project_directory, const char * depot_path) {
    // Prevent double initialization and initialization after finalization
    if (is_initialized) {
        print_and_die("trixi_initialize invoked multiple times", LOC);
    }
    if (is_finalized) {
        print_and_die("trixi_initialize invoked after trixi_finalize", LOC);
    }

The second safeguard is never reached, because is_finalized can only be set in finalize, and finalize can only run if is_initialized is set.

2. As expected, the Fortran interface definition is not captured.

3. Multi-Line statements in Fortran (with &) are not correctly handled.

4. test/fortran is checked for coverage (which is not really useful),
   test/c is not (maybe due to gtest magic creating executables out of nowhere?)

[sloede]

The second safeguard is never reached

Good point! Can you please remove the second check?

As expected, the Fortran interface definition is not captured.

Too bad, but nothing we can do here, I guess, but to remain vigilant ourselves.

test/fortran is checked for coverage (which is not really useful),
test/c is not (maybe due to gtest magic creating executables out of nowhere?)

Can you exclude test from coverage reporting?

[benegee]

All done! Excluding feels a little like cheating, but coverage increased!

[sloede]

Great work 🥳