extra unit test on keyword behaviour

[dorchard]

Adds a unit test on the behaviour of launch.m with partial data tiles missing some of the keywords. This uses the stdout of the MATLAB engine.

[j-emberton]

Did you base this branch off 'main' rather than test_launch.m?

It's slightly out of sync with my test_launch.m branch which you just reviewed. E.g. setup_folders fixture is now called setup_test_environment.

Otherwise it looks ok

[dorchard]

Hm. This is based off [refactor_and_test_launch](https://github.com/Cambridge-ICCS/ONEFlux/tree/refactor_and_test_launch). I'm using setup_test_environment, which I think is the most up-to-date name right?

[j-emberton]

Hm. This is based off [refactor_and_test_launch](https://github.com/Cambridge-ICCS/ONEFlux/tree/refactor_and_test_launch). I'm using setup_test_environment, which I think is the most up-to-date name right?

Sorry I got myself completely confused there, mixing up branch and PR names and all sorts. I think you're all good.