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Paul Gschwendtner
4e0cee52f0
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" ```
Angular
The sources for this package are in the main Angular repo. Please file issues and pull requests against that repo.
Usage information and reference details can be found in Angular documentation.
License: MIT