* Fix tests to use Ahem, and helpful changes around that
- Fix fonts that had metric-specific behaviours.
- LiveTestWidgetsFlutterBinding.allowAllFrames has been renamed
to LiveTestWidgetsFlutterBinding.framePolicy.
- LiveTestWidgetsFlutterBinding now defaults to using a frame policy
that pumps slightly more frames, to animate the pointer crosshairs.
- Added "flutter run --use-test-fonts" to enable Ahem on devices.
- Changed how idle() works to be more effective in live mode.
- Display the test name in live mode (unless ahem fonts are enabled).
- Added a toString to TextSelectionPoint.
- Style nit fixes.
* Roll engine to get Ahem changes.
* Update tests for dartdoc changes.
* Fix flutter_tools tests
Rename State.config to State.widget
Rename State.didUpdateConfig to State.didUpdateWidget
Renamed all State subclasses' local variables named config to something else
Breaking change: removed deprecated methods of PlatformMessages, leaving only binary messaging there. All other use of platform communication now goes through PlatformMessageChannel and PlatformMethodChannels. Retained use of String and JSON codecs for now.
Companion engine PR: flutter/engine#3482
* Bump to test `0.12.20`.
Some test `0.12.20` highlights:
* introduces `expectLater()` that returns a `Future` that completes when the matcher has finished running
* deprecates the `verbose` parameter to `expect()` and the `formatFailure()` (to be removed in `0.13.0`)
Otherwise:
* to keep up w/ the deprecation of `verbose`, removes `widget_tester` API to pass `verbose` flag (alternatively we could suppress the warning for now)
* Update stack manipulation.
* Fix framecount.
* Add find.descendant API to support find descendants of an element by passing the current element and the finder of descendant.
* Add find.descendant API to support find descendants of an element by passing the current element finder and the finder of descendant.
* Add find.descendant API to support find descendants of an element by passing the current element finder and the finder of descendant.
* Add find.descendant API to support find descendants of an element by passing the current element finder and the finder of descendant.
* Add find.descendant API to support find descendants of an element by passing the current element finder and the finder of descendant.
* Add find.descendant API to support find descendants of an element by passing the current element finder and the finder of descendant.
* Add find.descendant API to support find descendants of an element by passing the current element finder and the finder of descendant.
* Add find.descendant API to support find descendants of an element by passing the current element finder and the finder of descendant.
* Add find.descendant API to support find descendants of an element by passing the current element finder and the finder of descendant.
* Add find.descendant API to support find descendants of an element by passing the current element finder and the finder of descendant.
* Add find.descendant API to support find descendants of an element by passing the current element finder and the finder of descendant.
- output single-line JSON because iOS 9.x cannot output more than one line
- move the workaround for #7433 into LiveTestWidgetsFlutterBinding so that it works in all cases (e.g. animation_bench.dart on iOS)
Also, make hasOneLineDescription more discerning.
Also, add a test for hasOneLineDescription.
Also, add a test for GravitySimulation, to test the toString.
```dart
expect(x, moreOrLessEquals(0.0));
```
...for those cases where `x` might be 1e-11 or whatever.
Also, be more resilient when dumping the tree from inside the test framework.
Also, add an assert that helped me debug something the other day.
We were trying to update the tooltip overlay entry, but that cannot work
because the overlay entry might have already built. Instead, we keep the
old value.
Fixes#7151
