Unify index.ts files

[lovettchris]

Your test suite has 2 identical index.ts files, when you have 10 test suites this gets a bit old. Can you provide a way to unify the index.ts files so I only need one?

• make it so that runTests can pass another parameter to the index.ts run function?
• make it so I can customize the testsRoot path passed to the run function?