The behavior of `ComponentFixture` for zoneless tests was decided somewhat through guesswork, trial, and error. In addition, working on the zoneless fixture revealed oddities in the behavior of the zone-based fixture, or behaviors that we felt were counterintuitive. The most consequential difference is how change detection works: `detectChanges` goes through ApplicationRef.tick in zoneless while it is `changeDetectorRef.detectChanges` in the zone fixture.
We felt that running change detection through `ApplicationRef.tick` was important for several reasons:
* Aligning application behavior more closely with the test behavior (almost all views are attached to application ref in reality)
* Ensuring that afterRender* hooks are executed when calling `fixture.detectChanges`
* Ensuring that the change detection runs again if render hooks update state
This change, however, has some noticeable consequences that will break some tests, mostly around how errors are handled. `ApplicationRef.tick` catches errors that happen during change detection and reports them to the ErrorHandler from DI. The default error handler only logs the error to the console. This will break tests which have `expect(() => fixture.detectChanges()).toThrow()`. In addition, it allows tests to pass when there are real errors encountered during change detection.
This change ensures that errors from `ApplicationRef.tick` are rethrown
and will fail the test. We should also do a follow-up investigation to
determine whether we can/should also do this for the zone-based
`ComponentFixture`.
fixes#56977
PR Close#56993
3a63c9ebbe