Paul Gschwendtner
a462f91d3e
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" ```
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