Paul Gschwendtner 4e0cee52f0 fix(core): do not invoke jasmine done callback multiple times with waitForAsync ...

Currently tests written using `waitForAsync` would be prone to Jasmine
warnings or errors (depending on the version) for tests incorrectly
invoking asynchronous jasmine `done` callbacks multiple times.

This can happen because the async test zone logic schedules the
`done` callback to be called using `setTimeout`, but this could
be invoked multiple times, causing multiple `done` invocations to
be scheduled. Most of the issues have been resolved with #45025,
but it does not solve the case of multiple tasks finished and callbacks
being scheduled.

Technically, the current logic is built in way that _should_ result in
`_finishCallbackIfDone` and eventually the `done` callback to be invoked
at maximium once. This is unfortunately not the case in some rather
advanced/unexpected scenarios (like our AngularJS upgrade tests) where
the scenario is the following (and microtasks from before the actual
`waitForAsync` spec are still completing -- which is valid):

```
1. A test `beforeEach` schedules a microtask in the ProxyZone.
2. An actual empty `it` spec executes in the AsyncTestZone` (using e.g. `waitForAsync`).
3. The `onInvoke` invokes `_finishCallbackIfDone` because the spec runs synchronously.
4. We wait the scheduled timeout (see below) to account for unhandled promises.
5. The microtask from (1) finishes and `onHasTask` is invoked.

--> We register a second `_finishCallbackIfDone` even though we have scheduled a timeout.
--> we execute the `done` callback twice because the async zone spec state is "stable"
```

2022-07-18 19:19:00 +02:00

11 KiB

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