add a script to run a single test

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.

1 files changed, 1 insertions, 0 deletions

diff --git a/run_mypy.py b/run_mypy.py
index e6900c7..1c886f8 100755
--- a/run_mypy.py
+++ b/run_mypy.py
@@ -39,6 +39,7 @@ modules = [
     'mesonbuild/optinterpreter.py',
 
     'run_mypy.py',
+    'run_single_test.py',
     'tools'
 ]