Check out the roadmap to see what features need to be implemented.
Look around the code to spot code convention (two spaces for tabs, no semicolons at the end of lines, etc.). I’ll need those to be respected to accept a pull request.
Adding a test to a pull request isn’t mandatory.
Tests (in the tests folder) are PHP-generated HTML pages with which to check how InstantClick behaves on different browsers. That’s what I use before releasing a new version to make sure there are no obvious regressions.
To access the suite of tests, run php -S 127.0.0.1:8000 from the project’s root directory (not from the tests folder) and head to http://127.0.0.1:8000/tests/.