[DX] run test on non-builded codebase

[jdeniau]

I open this issue as for a first time contributor I ran into some bumps on the road :

To run tests, I have to "build" the project, as apparently the test run on the compiled version of the code.

Otherwise, if you clone a fresh project and run yarn install && yarn test it does throw an exception about missing files.

One more "issue" with that is that the stacktrace in the test suite reports incorrect files and line numbers.

So my question here is that :

• do I use it "the wrong way"?
• is this a "feature" / is this needed?