Add a method to enable REPL-like debugging on e2e tests

[cvializ]

I got sick of debugging and having the test timeout and having to put a debugger statement and then not being able to call methods on the controller.

// before:
it('should do stuff', async() => {
  debugger;
  // even if you called `await controller.getTitle()` in the console, 
  // nothing would happen because test execution is stopped and
  // async calls do not complete. If too much time passes the test will timeout.
});

// after:
it('should do stuff', async function() {
  await repl(this);
  // Now if you called `await controller.getTitle()` in the console,
  // you'll get `"Page Title"`.
});

These calls are for debugging only and should not be checked in to the repo.

Demo (internal only): https://drive.google.com/file/d/1KtJjcy8o8oSdax1MChvCWGEpgYJFoco-/view?usp=sharing

[sparhami]

Could just return totalPromise.then. Can you just turn this whole function into async/await instead?

for (const fixture of fixtures) {
  await fixture.setup(env);
}
await installRepl(global, env);

If not, would consider:

let totalPromise = Promise.resolve();
fixtures.forEach((fixture) => {
  totalPromise = totalPromise.then(() => fixture.setup(env));
});
return totalPromise.then(() => {
  installRepl(global, env);
});

[cvializ]

That's a huge improvement. I was originally thinking about maintaining parity with the original describes.js file, but I think the win here is worth it.

[sparhami]

Seems like you could have the describes-e2e code keep track of mochaThis (I think inside of describe(SUB, function() {...}, and then have this code just grab it. Then developers wouldn't need to change their arrow functions.

[cvializ]

Unfortunately I tried a few ways of using various mocha this values, but the one from the currently running it is the only this that actually changes the timeout. Using cached this values will cause the test to exit at 20000ms, which is the default this for the e2e test, which I assume is because the current it's this takes precedence?

[sparhami]

I suppose they have different this values. Maybe there is a way to wrap it, but I suppose we could always come back to it if we have time.

[cvializ]

Sounds good, it would be great to simplify this but I agree that iterating on it later would be best

[sparhami]

consider changing to an early return

[cvializ]

PTAL