[flutter_test] new WidgetTester API based on finder objects

dev/manual_tests/test/card_collection_test.dart

@@ -15,27 +15,27 @@ void main() {
       tester.pump(); // see https://github.com/flutter/flutter/issues/1865
       tester.pump(); // triggers a frame
 
-      Element navigationMenu = tester.findElement((Element element) {
+      Finder navigationMenu = find.byElement((Element element) {
         Widget widget = element.widget;
         if (widget is Tooltip)
           return widget.message == 'Open navigation menu';
         return false;
       });
 
-      expect(navigationMenu, isNotNull);
+      expect(tester, hasWidget(navigationMenu));
 
       tester.tap(navigationMenu);
       tester.pump(); // start opening menu
       tester.pump(const Duration(seconds: 1)); // wait til it's really opened
 
       // smoke test for various checkboxes
-      tester.tap(tester.findText('Make card labels editable'));
+      tester.tap(find.text('Make card labels editable'));
       tester.pump();
-      tester.tap(tester.findText('Let the sun shine'));
+      tester.tap(find.text('Let the sun shine'));
       tester.pump();
-      tester.tap(tester.findText('Make card labels editable'));
+      tester.tap(find.text('Make card labels editable'));
       tester.pump();
-      tester.tap(tester.findText('Vary font sizes'));
+      tester.tap(find.text('Vary font sizes'));
       tester.pump();
     });
   });

examples/hello_world/test/hello_test.dart

@@ -13,7 +13,7 @@ void main() {
       hello_world.main(); // builds the app and schedules a frame but doesn't trigger one
       tester.pump(); // triggers a frame
 
-      expect(tester.findText('Hello, world!'), isNotNull);
+      expect(tester, hasWidget(find.text('Hello, world!')));
     });
   });
 }

examples/material_gallery/test/smoke_test.dart

@@ -16,45 +16,45 @@ void main() {
       tester.pump(); // triggers a frame
 
       // Try loading Weather demo
-      tester.tap(tester.findText('Demos'));
+      tester.tap(find.text('Demos'));
       tester.pump();
       tester.pump(const Duration(seconds: 1)); // wait til it's really opened
 
-      tester.tap(tester.findText('Weather'));
+      tester.tap(find.text('Weather'));
       tester.pump();
       tester.pump(const Duration(seconds: 1)); // wait til it's really opened
 
       // Go back
-      Element backButton = tester.findElement((Element element) {
+      Finder backButton = find.byElement((Element element) {
         Widget widget = element.widget;
         if (widget is Tooltip)
           return widget.message == 'Back';
         return false;
       });
-      expect(backButton, isNotNull);
+      expect(tester, hasWidget(backButton));
       tester.tap(backButton);
       tester.pump(); // start going back
       tester.pump(const Duration(seconds: 1)); // wait til it's finished
 
       // Open menu
-      Element navigationMenu = tester.findElement((Element element) {
+      Finder navigationMenu = find.byElement((Element element) {
         Widget widget = element.widget;
         if (widget is Tooltip)
           return widget.message == 'Open navigation menu';
         return false;
       });
-      expect(navigationMenu, isNotNull);
+      expect(tester, hasWidget(navigationMenu));
       tester.tap(navigationMenu);
       tester.pump(); // start opening menu
       tester.pump(const Duration(seconds: 1)); // wait til it's really opened
 
       // switch theme
-      tester.tap(tester.findText('Dark'));
+      tester.tap(find.text('Dark'));
       tester.pump();
       tester.pump(const Duration(seconds: 1)); // wait til it's changed
 
       // switch theme
-      tester.tap(tester.findText('Light'));
+      tester.tap(find.text('Light'));
       tester.pump();
       tester.pump(const Duration(seconds: 1)); // wait til it's changed
     });

examples/stocks/test/icon_color_test.dart

@@ -38,7 +38,7 @@ Element findElementOfExactWidgetTypeGoingUp(Element node, Type targetType) {
 
 final RegExp materialIconAssetNameColorExtractor = new RegExp(r'[^/]+/ic_.+_(white|black)_[0-9]+dp\.png');
 
-void checkIconColor(WidgetTester tester, String label, Color color) {
+void checkIconColor(ElementTreeTester tester, String label, Color color) {
   // The icon is going to be in the same merged semantics box as the text
   // regardless of how the menu item is represented, so this is a good
   // way to find the menu item. I hope.
@@ -59,11 +59,11 @@ void main() {
       tester.pump(); // triggers a frame
 
       // sanity check
-      expect(tester.findText('MARKET'), isNotNull);
-      expect(tester.findText('Help & Feedback'), isNull);
+      expect(tester, hasWidget(find.text('MARKET')));
+      expect(tester, doesNotHaveWidget(find.text('Help & Feedback')));
       tester.pump(new Duration(seconds: 2));
-      expect(tester.findText('MARKET'), isNotNull);
-      expect(tester.findText('Help & Feedback'), isNull);
+      expect(tester, hasWidget(find.text('MARKET')));
+      expect(tester, doesNotHaveWidget(find.text('Help & Feedback')));
 
       // drag the drawer out
       Point left = new Point(0.0, ui.window.size.height / 2.0);
@@ -74,24 +74,24 @@ void main() {
       tester.pump();
       gesture.up();
       tester.pump();
-      expect(tester.findText('MARKET'), isNotNull);
-      expect(tester.findText('Help & Feedback'), isNotNull);
+      expect(tester, hasWidget(find.text('MARKET')));
+      expect(tester, hasWidget(find.text('Help & Feedback')));
 
       // check the colour of the icon - light mode
-      checkIconColor(tester, 'Stock List', Colors.purple[500]); // theme primary color
-      checkIconColor(tester, 'Account Balance', Colors.black45); // enabled
-      checkIconColor(tester, 'Help & Feedback', Colors.black26); // disabled
+      checkIconColor(tester.elementTreeTester, 'Stock List', Colors.purple[500]); // theme primary color
+      checkIconColor(tester.elementTreeTester, 'Account Balance', Colors.black45); // enabled
+      checkIconColor(tester.elementTreeTester, 'Help & Feedback', Colors.black26); // disabled
 
       // switch to dark mode
-      tester.tap(tester.findText('Pessimistic'));
+      tester.tap(find.text('Pessimistic'));
       tester.pump(); // get the tap and send the notification that the theme has changed
       tester.pump(); // start the theme transition
       tester.pump(const Duration(seconds: 5)); // end the transition
 
       // check the colour of the icon - dark mode
-      checkIconColor(tester, 'Stock List', Colors.redAccent[200]); // theme accent color
-      checkIconColor(tester, 'Account Balance', Colors.white); // enabled
-      checkIconColor(tester, 'Help & Feedback', Colors.white30); // disabled
+      checkIconColor(tester.elementTreeTester, 'Stock List', Colors.redAccent[200]); // theme accent color
+      checkIconColor(tester.elementTreeTester, 'Account Balance', Colors.white); // enabled
+      checkIconColor(tester.elementTreeTester, 'Help & Feedback', Colors.white30); // disabled
 
     });
   });

examples/stocks/test/locale_test.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:stocks/main.dart' as stocks;
 import 'package:stocks/stock_data.dart' as stock_data;
@@ -14,15 +13,13 @@ void main() {
   test("Test changing locale", () {
     testWidgets((WidgetTester tester) {
       stocks.main();
-      tester.async.flushMicrotasks(); // see https://github.com/flutter/flutter/issues/1865
+      tester.flushMicrotasks(); // see https://github.com/flutter/flutter/issues/1865
       tester.pump();
 
-      Element tab = tester.findText('MARKET');
-      expect(tab, isNotNull);
+      expect(tester, hasWidget(find.text('MARKET')));
       tester.setLocale("es", "US");
       tester.pump();
-      Text text = tab.widget;
-      expect(text.data, equals("MERCADO"));
+      expect(tester, hasWidget(find.text('MERCADO')));
 
       // TODO(abarth): We're leaking an animation. We should track down the leak
       // and plug it rather than waiting for the animation to end here.

packages/flutter/benchmark/stocks/build_bench.dart

@@ -24,7 +24,7 @@ void main() {
     tester.tapAt(new Point(20.0, 20.0)); // Open drawer
     tester.pump(); // Start drawer animation
     tester.pump(const Duration(seconds: 1)); // Complete drawer animation
-    appState = tester.findStateOfType(stocks.StocksAppState);
+    appState = tester.stateOf(find.byType(stocks.StocksApp));
   });
 
   WidgetFlutterBinding binding = WidgetFlutterBinding.instance;

packages/flutter/test/material/slider_test.dart

@@ -34,7 +34,7 @@ void main() {
       );
 
       expect(value, equals(0.0));
-      tester.tap(tester.findElementByKey(sliderKey));
+      tester.tap(find.byKey(sliderKey));
       expect(value, equals(0.5));
       tester.pump(); // No animation should start.
       expect(Scheduler.instance.transientCallbackCount, equals(0));
@@ -70,11 +70,11 @@ void main() {
       );
 
       expect(value, equals(0.0));
-      tester.tap(tester.findElementByKey(sliderKey));
+      tester.tap(find.byKey(sliderKey));
       expect(value, equals(50.0));
-      tester.scroll(tester.findElementByKey(sliderKey), const Offset(5.0, 0.0));
+      tester.scroll(find.byKey(sliderKey), const Offset(5.0, 0.0));
       expect(value, equals(50.0));
-      tester.scroll(tester.findElementByKey(sliderKey), const Offset(40.0, 0.0));
+      tester.scroll(find.byKey(sliderKey), const Offset(40.0, 0.0));
       expect(value, equals(80.0));
 
       tester.pump(); // Starts animation.