Usage of initializer causes race condition in tests.

[rwjblue]

Since initializers are not ran for moduleFor and moduleForComponent tests, those tests will be using the non-Ember specific spaniel engine (which is not run-loop aware). The first time that a spaniel call is made the spaniel internal variable globalEngine is setup (defaulting to the "normal" spaniel engine) and cannot be reset.

As you can see here:

let globalEngine: EngineInterface = null;

export function setGlobalEngine(engine: EngineInterface): boolean {
  if (!!globalEngine) {
    return false;
  }
  globalEngine = engine;
  return true;
}

export function getGlobalEngine() {
  return globalEngine || (globalEngine = new Engine());
}

This means that in any circumstance where a moduleFor or moduleForComponent test is ran before a moduleForAcceptance (the only tests prior to emberjs/rfcs#232 and emberjs/rfcs#268 that actually run initializers) the entire rest of the test run is going to run with the incorrect spaniel engine.

---

The fix is straightforward, this initializer should be removed:

https://github.com/asakusuma/ember-spaniel/blob/066cfdaf16ea3e939e1fdd440745c04ccdc4ea64/addon/initializers/spaniel.js#L4-L11

Instead, the custom spaniel engine should be moved to vendor/ and app.import'ed directly.

The app.imported code will always run (completely independent of the initialization process of an application), and everything will be 🌞 and 🌈 .

[asakusuma]

@lynchbomb does it make sense to fix this with the impending v3 spaniel release which removes setGlobalEngine?

[lynchbomb]

This is fixed once the Ember-Spaniel#v1.x and Spaniel#v4.x releases are rolled-out. setGlobalEngine is a thing of the past.