Allow passing an optional timeout to Testability's whenStable(). If
specified, if Angular is not stable before the timeout is hit, the
done callback will be invoked with a list of pending macrotasks.
Also, allows an optional update callback, which will be invoked whenever
the set of pending macrotasks changes. If this callback returns true,
the timeout will be cancelled and the done callback will not be invoked.
If the optional parameters are not passed, whenStable() will work
as it did before, whether or not the task tracking zone spec is
available.
This change also migrates the Testability unit tests off the deprecated
AsyncTestCompleter.
PR Close#16863
Closes#10503
It is possible for code in `beforeEach` to capture and fork a zone
(for example creating `NgZone` in `beforeEach`). Subsequently the code
in `it` may chose to do `fakeAsync`. The issue is that because the
code in `it` can use `NgZone` from the `beforeEach`. it effectively can
escape the `fakeAsync` zone. A solution is to run all of the test in
`ProxyZone` which allows a test to dynamically replace the rules at any
time. This allows the `beforeEach` to fork a zone, and then `it` to
retroactively became `fakeAsync` zone.
George Kalpakas
Michael Giambalvo
Tobias Bosch
Joao Dias
Marc Laval
Julie Ralph
Miško Hevery
Alex Eagle