This can be the longest part of the entire test process, often with no
benefit because we already know the environment is sane. So, let's have
an option save some time.
We expose a reason after the string 'MESON_SKIP_TEST', but it is
actually ignored when running the test, so it is only useful as
documentation and really might as well be a comment.
Make it even more useful by actually printing that string after the
'[SKIPPED]' message.
Also, sometimes a test can be skipped for multiple reasons, and it would
be useful to know which one occurred.
As a Meson developer it's often frustrating to have a single functional
test with a regression. These tests can be awkward to reproduce,
especially when they make use of a test.json file. This script provides
a simmple interface to call functional tests 1 at a time, regardless of
whether they use a test.json or not. If they do use a test.json, and
have a matrix, then the `--subtest` option can be used to select spcific
combinations, for example:
```sh
./run_single_test.py "test cases/frameworks/15 llvm" --subtest 1
```
will run only the second (zero indexed of course) subtest from the llvm
test cases.
This is not a super elegent script, but this is super useful.
Dylan Baker
Eli Schwartz
Jon Turney
Daniel Mensinger