add part of contributor's guide about running and writing tests
For adding a new core feature or fixing a bug, tests need to be run and created.
For porting stuff, here's a guide:
- Diff the contents against the version of Pd from which you're porting.
- Notice any differences in the diff and note the functions
- For each relevant function do
git log -L :<funcname>:<file>where "funcname" is the name of the function where a change happened and "file" is the filename. (Often it only takes one try to find the relevant commits for all the relevant changed code. But if not, repeat with the next function...)
- Read the commit message for any relevant commits to understand why there might be discrepancies.
- Start porting the changes.
- Get it compiling.
- Run the regression tests.
- Write new tests for the code that was added.