diff --git a/engine/src/flutter/lib/web_ui/dev/browser.dart b/engine/src/flutter/lib/web_ui/dev/browser.dart
index 43015a37517..5f1d31774c5 100644
--- a/engine/src/flutter/lib/web_ui/dev/browser.dart
+++ b/engine/src/flutter/lib/web_ui/dev/browser.dart
@@ -10,8 +10,6 @@ import 'package:pedantic/pedantic.dart';
 import 'package:stack_trace/stack_trace.dart';
 import 'package:typed_data/typed_buffers.dart';
 
-import 'package:test_api/src/utils.dart' show getErrorMessage;
-
 /// An interface for running browser instances.
 ///
 /// This is intentionally coarse-grained: browsers are controlled primary from
@@ -123,8 +121,9 @@ abstract class Browser {
         return;
       }
       _onExitCompleter.completeError(
-          Exception('Failed to run $name: ${getErrorMessage(error)}.'),
-          stackTrace);
+        Exception('Failed to run $name: $error.'),
+        stackTrace,
+      );
     });
   }
 
diff --git a/engine/src/flutter/lib/web_ui/pubspec.yaml b/engine/src/flutter/lib/web_ui/pubspec.yaml
index dfd598452ef..daabb9d19c8 100644
--- a/engine/src/flutter/lib/web_ui/pubspec.yaml
+++ b/engine/src/flutter/lib/web_ui/pubspec.yaml
@@ -16,7 +16,7 @@ dev_dependencies:
   image: 3.0.1
   path: 1.8.0
   quiver: 3.0.0
-  test: 1.16.6
+  test: 1.17.7
   yaml: 3.0.0
   watcher: 1.0.0
   web_test_utils:
diff --git a/engine/src/flutter/lib/web_ui/test/text_editing_test.dart b/engine/src/flutter/lib/web_ui/test/text_editing_test.dart
index 143e6ffaef8..44db0a3dc53 100644
--- a/engine/src/flutter/lib/web_ui/test/text_editing_test.dart
+++ b/engine/src/flutter/lib/web_ui/test/text_editing_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.
 
-// @dart = 2.9
 import 'dart:async';
 import 'dart:html';
 import 'dart:js_util' as js_util;
@@ -23,9 +22,9 @@ const MethodCodec codec = JSONMethodCodec();
 /// Add unit tests for [FirefoxTextEditingStrategy].
 /// TODO(nurhan): https://github.com/flutter/flutter/issues/46891
 
-DefaultTextEditingStrategy editingStrategy;
-EditingState lastEditingState;
-String lastInputAction;
+DefaultTextEditingStrategy? editingStrategy;
+EditingState? lastEditingState;
+String? lastInputAction;
 
 final InputConfiguration singlelineConfig = InputConfiguration(
   inputType: EngineInputType.text,
@@ -40,11 +39,11 @@ final InputConfiguration multilineConfig = InputConfiguration(
 final Map<String, dynamic> flutterMultilineConfig =
     createFlutterConfig('multiline');
 
-void trackEditingState(EditingState editingState) {
+void trackEditingState(EditingState? editingState) {
   lastEditingState = editingState;
 }
 
-void trackInputAction(String inputAction) {
+void trackInputAction(String? inputAction) {
   lastInputAction = inputAction;
 }
 
@@ -62,7 +61,7 @@ void testMain() {
   });
 
   group('$GloballyPositionedTextEditingStrategy', () {
-    HybridTextEditing testTextEditing;
+    late HybridTextEditing testTextEditing;
 
     setUp(() {
       testTextEditing = HybridTextEditing();
@@ -82,7 +81,7 @@ void testMain() {
       expect(document.activeElement, document.body);
       expect(defaultTextEditingRoot.activeElement, null);
 
-      editingStrategy.enable(
+      editingStrategy!.enable(
         singlelineConfig,
         onChange: trackEditingState,
         onAction: trackInputAction,
@@ -92,19 +91,19 @@ void testMain() {
         defaultTextEditingRoot.querySelectorAll('input'),
         hasLength(1),
       );
-      final InputElement input = defaultTextEditingRoot.querySelector('input');
+      final Element input = defaultTextEditingRoot.querySelector('input')!;
       // Now the editing element should have focus.
 
       expect(document.activeElement, domRenderer.glassPaneElement);
       expect(defaultTextEditingRoot.activeElement, input);
 
-      expect(editingStrategy.domElement, input);
+      expect(editingStrategy!.domElement, input);
       expect(input.getAttribute('type'), null);
 
       // Input is appended to the right point of the DOM.
-      expect(defaultTextEditingRoot.contains(editingStrategy.domElement), isTrue);
+      expect(defaultTextEditingRoot.contains(editingStrategy!.domElement), isTrue);
 
-      editingStrategy.disable();
+      editingStrategy!.disable();
       expect(
         defaultTextEditingRoot.querySelectorAll('input'),
         hasLength(0),
@@ -118,78 +117,78 @@ void testMain() {
       final InputConfiguration config = InputConfiguration(
         readOnly: true,
       );
-      editingStrategy.enable(
+      editingStrategy!.enable(
         config,
         onChange: trackEditingState,
         onAction: trackInputAction,
       );
       expect(defaultTextEditingRoot.querySelectorAll('input'), hasLength(1));
-      final InputElement input = defaultTextEditingRoot.querySelector('input');
-      expect(editingStrategy.domElement, input);
+      final Element input = defaultTextEditingRoot.querySelector('input')!;
+      expect(editingStrategy!.domElement, input);
       expect(input.getAttribute('readonly'), 'readonly');
 
-      editingStrategy.disable();
+      editingStrategy!.disable();
     });
 
     test('Knows how to create password fields', () {
       final InputConfiguration config = InputConfiguration(
         obscureText: true,
       );
-      editingStrategy.enable(
+      editingStrategy!.enable(
         config,
         onChange: trackEditingState,
         onAction: trackInputAction,
       );
       expect(defaultTextEditingRoot.querySelectorAll('input'), hasLength(1));
-      final InputElement input = defaultTextEditingRoot.querySelector('input');
-      expect(editingStrategy.domElement, input);
+      final Element input = defaultTextEditingRoot.querySelector('input')!;
+      expect(editingStrategy!.domElement, input);
       expect(input.getAttribute('type'), 'password');
 
-      editingStrategy.disable();
+      editingStrategy!.disable();
     });
 
     test('Knows to turn autocorrect off', () {
       final InputConfiguration config = InputConfiguration(
         autocorrect: false,
       );
-      editingStrategy.enable(
+      editingStrategy!.enable(
         config,
         onChange: trackEditingState,
         onAction: trackInputAction,
       );
       expect(defaultTextEditingRoot.querySelectorAll('input'), hasLength(1));
-      final InputElement input = defaultTextEditingRoot.querySelector('input');
-      expect(editingStrategy.domElement, input);
+      final Element input = defaultTextEditingRoot.querySelector('input')!;
+      expect(editingStrategy!.domElement, input);
       expect(input.getAttribute('autocorrect'), 'off');
 
-      editingStrategy.disable();
+      editingStrategy!.disable();
     });
 
     test('Knows to turn autocorrect on', () {
       final InputConfiguration config = InputConfiguration(
         autocorrect: true,
       );
-      editingStrategy.enable(
+      editingStrategy!.enable(
         config,
         onChange: trackEditingState,
         onAction: trackInputAction,
       );
       expect(defaultTextEditingRoot.querySelectorAll('input'), hasLength(1));
-      final InputElement input = defaultTextEditingRoot.querySelector('input');
-      expect(editingStrategy.domElement, input);
+      final Element input = defaultTextEditingRoot.querySelector('input')!;
+      expect(editingStrategy!.domElement, input);
       expect(input.getAttribute('autocorrect'), 'on');
 
-      editingStrategy.disable();
+      editingStrategy!.disable();
     });
 
     test('Can read editing state correctly', () {
-      editingStrategy.enable(
+      editingStrategy!.enable(
         singlelineConfig,
         onChange: trackEditingState,
         onAction: trackInputAction,
       );
 
-      final InputElement input = editingStrategy.domElement;
+      final InputElement input = editingStrategy!.domElement as InputElement;
       input.value = 'foo bar';
       input.dispatchEvent(Event.eventType('Event', 'input'));
       expect(
@@ -209,15 +208,15 @@ void testMain() {
     });
 
     test('Can set editing state correctly', () {
-      editingStrategy.enable(
+      editingStrategy!.enable(
         singlelineConfig,
         onChange: trackEditingState,
         onAction: trackInputAction,
       );
-      editingStrategy.setEditingState(
+      editingStrategy!.setEditingState(
           EditingState(text: 'foo bar baz', baseOffset: 2, extentOffset: 7));
 
-      checkInputEditingState(editingStrategy.domElement, 'foo bar baz', 2, 7);
+      checkInputEditingState(editingStrategy!.domElement!, 'foo bar baz', 2, 7);
 
       // There should be no input action.
       expect(lastInputAction, isNull);
@@ -226,7 +225,7 @@ void testMain() {
     test('Multi-line mode also works', () {
       // The textarea element is created lazily.
       expect(document.getElementsByTagName('textarea'), hasLength(0));
-      editingStrategy.enable(
+      editingStrategy!.enable(
         multilineConfig,
         onChange: trackEditingState,
         onAction: trackInputAction,
@@ -234,10 +233,10 @@ void testMain() {
       expect(defaultTextEditingRoot.querySelectorAll('textarea'), hasLength(1));
 
       final TextAreaElement textarea =
-          defaultTextEditingRoot.querySelector('textarea');
+          defaultTextEditingRoot.querySelector('textarea') as TextAreaElement;
       // Now the textarea should have focus.
       expect(defaultTextEditingRoot.activeElement, textarea);
-      expect(editingStrategy.domElement, textarea);
+      expect(editingStrategy!.domElement, textarea);
 
       textarea.value = 'foo\nbar';
       textarea.dispatchEvent(Event.eventType('Event', 'input'));
@@ -250,11 +249,11 @@ void testMain() {
       );
 
       // Can set textarea state correctly (and preserves new lines).
-      editingStrategy.setEditingState(
+      editingStrategy!.setEditingState(
           EditingState(text: 'bar\nbaz', baseOffset: 2, extentOffset: 7));
       checkTextAreaEditingState(textarea, 'bar\nbaz', 2, 7);
 
-      editingStrategy.disable();
+      editingStrategy!.disable();
       // The textarea should be cleaned up.
       expect(defaultTextEditingRoot.querySelectorAll('textarea'), hasLength(0));
       // The focus is back to the body.
@@ -270,7 +269,7 @@ void testMain() {
       expect(document.getElementsByTagName('textarea'), hasLength(0));
 
       // Use single-line config and expect an `<input>` to be created.
-      editingStrategy.enable(
+      editingStrategy!.enable(
         singlelineConfig,
         onChange: trackEditingState,
         onAction: trackInputAction,
@@ -279,12 +278,12 @@ void testMain() {
       expect(defaultTextEditingRoot.querySelectorAll('textarea'), hasLength(0));
 
       // Disable and check that all DOM elements were removed.
-      editingStrategy.disable();
+      editingStrategy!.disable();
       expect(defaultTextEditingRoot.querySelectorAll('input'), hasLength(0));
       expect(defaultTextEditingRoot.querySelectorAll('textarea'), hasLength(0));
 
       // Use multi-line config and expect an `<textarea>` to be created.
-      editingStrategy.enable(
+      editingStrategy!.enable(
         multilineConfig,
         onChange: trackEditingState,
         onAction: trackInputAction,
@@ -293,7 +292,7 @@ void testMain() {
       expect(defaultTextEditingRoot.querySelectorAll('textarea'), hasLength(1));
 
       // Disable again and check that all DOM elements were removed.
-      editingStrategy.disable();
+      editingStrategy!.disable();
       expect(defaultTextEditingRoot.querySelectorAll('input'), hasLength(0));
       expect(defaultTextEditingRoot.querySelectorAll('textarea'), hasLength(0));
 
@@ -305,7 +304,7 @@ void testMain() {
       final InputConfiguration config = InputConfiguration(
         inputAction: 'TextInputAction.done',
       );
-      editingStrategy.enable(
+      editingStrategy!.enable(
         config,
         onChange: trackEditingState,
         onAction: trackInputAction,
@@ -315,7 +314,7 @@ void testMain() {
       expect(lastInputAction, isNull);
 
       dispatchKeyboardEvent(
-        editingStrategy.domElement,
+        editingStrategy!.domElement!,
         'keydown',
         keyCode: _kReturnKeyCode,
       );
@@ -329,7 +328,7 @@ void testMain() {
         inputType: EngineInputType.multiline,
         inputAction: 'TextInputAction.done',
       );
-      editingStrategy.enable(
+      editingStrategy!.enable(
         config,
         onChange: trackEditingState,
         onAction: trackInputAction,
@@ -339,7 +338,7 @@ void testMain() {
       expect(lastInputAction, isNull);
 
       final KeyboardEvent event = dispatchKeyboardEvent(
-        editingStrategy.domElement,
+        editingStrategy!.domElement!,
         'keydown',
         keyCode: _kReturnKeyCode,
       );
@@ -351,17 +350,17 @@ void testMain() {
     });
 
     test('globally positions and sizes its DOM element', () {
-      editingStrategy.enable(
+      editingStrategy!.enable(
         singlelineConfig,
         onChange: trackEditingState,
         onAction: trackInputAction,
       );
-      expect(editingStrategy.isEnabled, isTrue);
+      expect(editingStrategy!.isEnabled, isTrue);
 
       // No geometry should be set until setEditableSizeAndTransform is called.
-      expect(editingStrategy.domElement.style.transform, '');
-      expect(editingStrategy.domElement.style.width, '');
-      expect(editingStrategy.domElement.style.height, '');
+      expect(editingStrategy!.domElement!.style.transform, '');
+      expect(editingStrategy!.domElement!.style.width, '');
+      expect(editingStrategy!.domElement!.style.height, '');
 
       testTextEditing.acceptCommand(TextInputSetEditableSizeAndTransform(geometry: EditableTextGeometry(
         width: 13,
@@ -370,30 +369,33 @@ void testMain() {
       )), () {});
 
       // setEditableSizeAndTransform calls placeElement, so expecting geometry to be applied.
-      expect(editingStrategy.domElement.style.transform,
+      expect(editingStrategy!.domElement!.style.transform,
           'matrix(1, 0, 0, 1, 14, 15)');
-      expect(editingStrategy.domElement.style.width, '13px');
-      expect(editingStrategy.domElement.style.height, '12px');
+      expect(editingStrategy!.domElement!.style.width, '13px');
+      expect(editingStrategy!.domElement!.style.height, '12px');
     });
   });
 
   group('$HybridTextEditing', () {
-    HybridTextEditing textEditing;
+    HybridTextEditing? textEditing;
     final PlatformMessagesSpy spy = PlatformMessagesSpy();
 
     int clientId = 0;
 
     /// Emulates sending of a message by the framework to the engine.
     void sendFrameworkMessage(dynamic message) {
-      textEditing.channel.handleTextInput(message, (ByteData data) {});
+      textEditing!.channel.handleTextInput(message, (ByteData? data) {});
     }
 
     /// Sends the necessary platform messages to activate a text field and show
     /// the keyboard.
     ///
     /// Returns the `clientId` used in the platform message.
-    int showKeyboard(
-        {String inputType, String inputAction, bool decimal = false}) {
+    int showKeyboard({
+      required String inputType,
+      String? inputAction,
+      bool decimal = false,
+    }) {
       final MethodCall setClient = MethodCall(
         'TextInput.setClient',
         <dynamic>[
@@ -419,7 +421,7 @@ void testMain() {
     }
 
     String getEditingInputMode() {
-      return textEditing.strategy.domElement.getAttribute('inputmode');
+      return textEditing!.strategy.domElement!.getAttribute('inputmode')!;
     }
 
     setUp(() {
@@ -429,8 +431,8 @@ void testMain() {
 
     tearDown(() {
       spy.tearDown();
-      if (textEditing.isEditing) {
-        textEditing.stopEditing();
+      if (textEditing!.isEditing) {
+        textEditing!.stopEditing();
       }
       textEditing = null;
     });
@@ -453,7 +455,7 @@ void testMain() {
       const MethodCall show = MethodCall('TextInput.show');
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
-      checkInputEditingState(textEditing.strategy.domElement, '', 0, 0);
+      checkInputEditingState(textEditing!.strategy.domElement, '', 0, 0);
 
       const MethodCall setEditingState =
           MethodCall('TextInput.setEditingState', <String, dynamic>{
@@ -464,7 +466,7 @@ void testMain() {
       sendFrameworkMessage(codec.encodeMethodCall(setEditingState));
 
       checkInputEditingState(
-          textEditing.strategy.domElement, 'abcd', 2, 3);
+          textEditing!.strategy.domElement, 'abcd', 2, 3);
 
       const MethodCall hide = MethodCall('TextInput.hide');
       sendFrameworkMessage(codec.encodeMethodCall(hide));
@@ -496,7 +498,7 @@ void testMain() {
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
       checkInputEditingState(
-          textEditing.strategy.domElement, 'abcd', 2, 3);
+          textEditing!.strategy.domElement, 'abcd', 2, 3);
 
       const MethodCall clearClient = MethodCall('TextInput.clearClient');
       sendFrameworkMessage(codec.encodeMethodCall(clearClient));
@@ -527,7 +529,7 @@ void testMain() {
       const MethodCall show = MethodCall('TextInput.show');
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
-      final HtmlElement element = textEditing.strategy.domElement;
+      final Element element = textEditing!.strategy.domElement!;
       expect(element.getAttribute('readonly'), 'readonly');
 
       // Update the read-only config.
@@ -569,11 +571,11 @@ void testMain() {
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
       checkInputEditingState(
-          textEditing.strategy.domElement, 'abcd', 2, 3);
-      expect(textEditing.isEditing, isTrue);
+          textEditing!.strategy.domElement, 'abcd', 2, 3);
+      expect(textEditing!.isEditing, isTrue);
 
       // DOM element is blurred.
-      textEditing.strategy.domElement.blur();
+      textEditing!.strategy.domElement!.blur();
 
       // For ios-safari the connection is closed.
       if (browserEngine == BrowserEngine.webkit &&
@@ -591,7 +593,7 @@ void testMain() {
         await Future<void>.delayed(Duration.zero);
         // DOM element still keeps the focus.
         expect(defaultTextEditingRoot.activeElement,
-            textEditing.strategy.domElement);
+            textEditing!.strategy.domElement);
       }
     },
         // TODO(nurhan): https://github.com/flutter/flutter/issues/50769
@@ -618,7 +620,7 @@ void testMain() {
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
       checkInputEditingState(
-          textEditing.strategy.domElement, 'abcd', 2, 3);
+          textEditing!.strategy.domElement, 'abcd', 2, 3);
 
       const MethodCall finishAutofillContext =
           MethodCall('TextInput.finishAutofillContext', false);
@@ -733,7 +735,7 @@ void testMain() {
 
       // Form is added to DOM.
       expect(defaultTextEditingRoot.querySelectorAll('form'), isNotEmpty);
-      FormElement formElement = defaultTextEditingRoot.querySelector('form');
+      FormElement formElement = defaultTextEditingRoot.querySelector('form') as FormElement;
       final Completer<bool> submittedForm = Completer<bool>();
       formElement.addEventListener(
           'submit', (event) => submittedForm.complete(true));
@@ -786,7 +788,7 @@ void testMain() {
 
       // Form is added to DOM.
       expect(defaultTextEditingRoot.querySelectorAll('form'), isNotEmpty);
-      FormElement formElement = defaultTextEditingRoot.querySelector('form');
+      FormElement formElement = defaultTextEditingRoot.querySelector('form') as FormElement;
       final Completer<bool> submittedForm = Completer<bool>();
       formElement.addEventListener(
           'submit', (event) => submittedForm.complete(true));
@@ -830,7 +832,7 @@ void testMain() {
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
       checkInputEditingState(
-          textEditing.strategy.domElement, 'abcd', 2, 3);
+          textEditing!.strategy.domElement, 'abcd', 2, 3);
 
       final MethodCall setClient2 = MethodCall(
           'TextInput.setClient', <dynamic>[567, flutterSinglelineConfig]);
@@ -872,7 +874,7 @@ void testMain() {
 
       // The second [setEditingState] should override the first one.
       checkInputEditingState(
-          textEditing.strategy.domElement, 'xyz', 0, 2);
+          textEditing!.strategy.domElement, 'xyz', 0, 2);
 
       const MethodCall clearClient = MethodCall('TextInput.clearClient');
       sendFrameworkMessage(codec.encodeMethodCall(clearClient));
@@ -909,9 +911,9 @@ void testMain() {
 
       // The second [setEditingState] should override the first one.
       checkInputEditingState(
-          textEditing.strategy.domElement, 'abcd', 2, 3);
+          textEditing!.strategy.domElement, 'abcd', 2, 3);
 
-      final FormElement formElement = defaultTextEditingRoot.querySelector('form');
+      final FormElement formElement = defaultTextEditingRoot.querySelector('form') as FormElement;
       // The form has one input element and one submit button.
       expect(formElement.childNodes, hasLength(2));
 
@@ -947,7 +949,7 @@ void testMain() {
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
       final InputElement inputElement =
-          textEditing.strategy.domElement as InputElement;
+          textEditing!.strategy.domElement as InputElement;
       expect(inputElement.value, 'abcd');
       if (!(browserEngine == BrowserEngine.webkit &&
           operatingSystem == OperatingSystem.macOs)) {
@@ -968,11 +970,11 @@ void testMain() {
 
       // Check the element still has focus. User can keep editing.
       expect(defaultTextEditingRoot.activeElement,
-          textEditing.strategy.domElement);
+          textEditing!.strategy.domElement);
 
       // Check the cursor location is the same.
       checkInputEditingState(
-          textEditing.strategy.domElement, 'abcd', 2, 3);
+          textEditing!.strategy.domElement, 'abcd', 2, 3);
 
       const MethodCall clearClient = MethodCall('TextInput.clearClient');
       sendFrameworkMessage(codec.encodeMethodCall(clearClient));
@@ -1019,9 +1021,9 @@ void testMain() {
 
       // The second [setEditingState] should override the first one.
       checkInputEditingState(
-          textEditing.strategy.domElement, 'abcd', 2, 3);
+          textEditing!.strategy.domElement, 'abcd', 2, 3);
 
-      final FormElement formElement = defaultTextEditingRoot.querySelector('form');
+      final FormElement formElement = defaultTextEditingRoot.querySelector('form') as FormElement;
       // The form has 4 input elements and one submit button.
       expect(formElement.childNodes, hasLength(5));
 
@@ -1061,12 +1063,12 @@ void testMain() {
       if (browserEngine == BrowserEngine.webkit &&
           operatingSystem == OperatingSystem.iOs) {
         expect(
-            textEditing.strategy.domElement
+            textEditing!.strategy.domElement!
                 .getAttribute('autocapitalize'),
             'off');
       } else {
         expect(
-            textEditing.strategy.domElement
+            textEditing!.strategy.domElement!
                 .getAttribute('autocapitalize'),
             isNull);
       }
@@ -1100,7 +1102,7 @@ void testMain() {
       if (browserEngine == BrowserEngine.webkit &&
           operatingSystem == OperatingSystem.iOs) {
         expect(
-            textEditing.strategy.domElement
+            textEditing!.strategy.domElement!
                 .getAttribute('autocapitalize'),
             'characters');
       }
@@ -1136,7 +1138,7 @@ void testMain() {
       const MethodCall show = MethodCall('TextInput.show');
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
-      final HtmlElement domElement = textEditing.strategy.domElement;
+      final Element domElement = textEditing!.strategy.domElement!;
 
       checkInputEditingState(domElement, 'abcd', 2, 3);
 
@@ -1147,7 +1149,7 @@ void testMain() {
               const Point<double>(160.0, 70.0)));
       expect(domElement.style.transform,
           'matrix3d(1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 10, 20, 30, 1)');
-      expect(textEditing.strategy.domElement.style.font,
+      expect(textEditing!.strategy.domElement!.style.font,
           '500 12px sans-serif');
 
       const MethodCall clearClient = MethodCall('TextInput.clearClient');
@@ -1192,7 +1194,7 @@ void testMain() {
       });
       sendFrameworkMessage(codec.encodeMethodCall(setEditingState));
 
-      final HtmlElement domElement = textEditing.strategy.domElement;
+      final HtmlElement domElement = textEditing!.strategy.domElement!;
 
       checkInputEditingState(domElement, 'abcd', 2, 3);
 
@@ -1207,7 +1209,7 @@ void testMain() {
         'matrix3d(1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 10, 20, 30, 1)',
       );
       expect(
-        textEditing.strategy.domElement.style.font,
+        textEditing!.strategy.domElement!.style.font,
         '500 12px sans-serif',
       );
 
@@ -1215,11 +1217,11 @@ void testMain() {
       if (browserEngine == BrowserEngine.blink ||
           browserEngine == BrowserEngine.samsung ||
           browserEngine == BrowserEngine.webkit) {
-        expect(textEditing.strategy.domElement.classes,
+        expect(textEditing!.strategy.domElement!.classes,
             contains('transparentTextEditing'));
       } else {
         expect(
-            textEditing.strategy.domElement.classes.any(
+            textEditing!.strategy.domElement!.classes.any(
                 (element) => element.toString() == 'transparentTextEditing'),
             isFalse);
       }
@@ -1255,7 +1257,7 @@ void testMain() {
       const MethodCall show = MethodCall('TextInput.show');
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
-      final HtmlElement domElement = textEditing.strategy.domElement;
+      final HtmlElement domElement = textEditing!.strategy.domElement!;
 
       checkInputEditingState(domElement, 'abcd', 2, 3);
 
@@ -1267,7 +1269,7 @@ void testMain() {
       expect(domElement.style.transform,
           'matrix3d(1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 10, 20, 30, 1)');
       expect(
-          textEditing.strategy.domElement.style.font, '12px sans-serif');
+          textEditing!.strategy.domElement!.style.font, '12px sans-serif');
 
       hideKeyboard();
     },
@@ -1275,9 +1277,9 @@ void testMain() {
         skip: browserEngine == BrowserEngine.webkit);
 
     test('Canonicalizes font family', () {
-      showKeyboard();
+      showKeyboard(inputType: 'text');
 
-      final HtmlElement input = textEditing.strategy.domElement;
+      final HtmlElement input = textEditing!.strategy.domElement!;
 
       MethodCall setStyle;
 
@@ -1316,7 +1318,7 @@ void testMain() {
 
       // Check if the selection range is correct.
       checkInputEditingState(
-          textEditing.strategy.domElement, 'xyz', 1, 2);
+          textEditing!.strategy.domElement, 'xyz', 1, 2);
 
       const MethodCall setEditingState2 =
           MethodCall('TextInput.setEditingState', <String, dynamic>{
@@ -1328,7 +1330,7 @@ void testMain() {
 
       // The negative offset values are applied to the dom element as 0.
       checkInputEditingState(
-          textEditing.strategy.domElement, 'xyz', 0, 0);
+          textEditing!.strategy.domElement, 'xyz', 0, 0);
 
       hideKeyboard();
     });
@@ -1349,7 +1351,7 @@ void testMain() {
       const MethodCall show = MethodCall('TextInput.show');
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
-      final InputElement input = textEditing.strategy.domElement;
+      final InputElement input = textEditing!.strategy.domElement as InputElement;
 
       input.value = 'something';
       input.dispatchEvent(Event.eventType('Event', 'input'));
@@ -1373,7 +1375,7 @@ void testMain() {
       input.setSelectionRange(2, 5);
       if (browserEngine == BrowserEngine.firefox) {
         Event keyup = KeyboardEvent('keyup');
-        textEditing.strategy.domElement.dispatchEvent(keyup);
+        textEditing!.strategy.domElement!.dispatchEvent(keyup);
       } else {
         document.dispatchEvent(Event.eventType('Event', 'selectionchange'));
       }
@@ -1431,14 +1433,14 @@ void testMain() {
 
       // The second [setEditingState] should override the first one.
       checkInputEditingState(
-          textEditing.strategy.domElement, 'abcd', 2, 3);
+          textEditing!.strategy.domElement, 'abcd', 2, 3);
 
-      final FormElement formElement = defaultTextEditingRoot.querySelector('form');
+      final FormElement formElement = defaultTextEditingRoot.querySelector('form') as FormElement;
       // The form has 4 input elements and one submit button.
       expect(formElement.childNodes, hasLength(5));
 
       // Autofill one of the form elements.
-      InputElement element = formElement.childNodes.first;
+      InputElement element = formElement.childNodes.first as InputElement;
       if (browserEngine == BrowserEngine.firefox) {
         expect(element.name,
             BrowserAutofillHints.instance.flutterToEngine(hintForFirstElement));
@@ -1482,7 +1484,7 @@ void testMain() {
       const MethodCall show = MethodCall('TextInput.show');
       sendFrameworkMessage(codec.encodeMethodCall(show));
 
-      final TextAreaElement textarea = textEditing.strategy.domElement;
+      final TextAreaElement textarea = textEditing!.strategy.domElement as TextAreaElement;
       checkTextAreaEditingState(textarea, '', 0, 0);
 
       // Can set editing state and preserve new lines.
@@ -1500,7 +1502,7 @@ void testMain() {
       textarea.dispatchEvent(Event.eventType('Event', 'input'));
       textarea.setSelectionRange(2, 5);
       if (browserEngine == BrowserEngine.firefox) {
-        textEditing.strategy.domElement
+        textEditing!.strategy.domElement!
             .dispatchEvent(KeyboardEvent('keyup'));
       } else {
         document.dispatchEvent(Event.eventType('Event', 'selectionchange'));
@@ -1624,7 +1626,7 @@ void testMain() {
       expect(lastInputAction, isNull);
 
       dispatchKeyboardEvent(
-        textEditing.strategy.domElement,
+        textEditing!.strategy.domElement!,
         'keydown',
         keyCode: _kReturnKeyCode,
       );
@@ -1647,7 +1649,7 @@ void testMain() {
       );
 
       final KeyboardEvent event = dispatchKeyboardEvent(
-        textEditing.strategy.domElement,
+        textEditing!.strategy.domElement!,
         'keydown',
         keyCode: _kReturnKeyCode,
       );
@@ -1670,7 +1672,7 @@ void testMain() {
           ['field1', 'field2', 'field3']);
       final EngineAutofillForm autofillForm =
           EngineAutofillForm.fromFrameworkMessage(
-              createAutofillInfo('username', 'field1'), fields);
+              createAutofillInfo('username', 'field1'), fields)!;
 
       // Number of elements if number of fields sent to the constructor minus
       // one (for the focused text element).
@@ -1685,7 +1687,7 @@ void testMain() {
       // 3 child nodes.
       expect(form.childNodes, hasLength(3));
 
-      final InputElement firstElement = form.childNodes.first;
+      final InputElement firstElement = form.childNodes.first as InputElement;
       // Autofill value is applied to the element.
       expect(firstElement.name,
           BrowserAutofillHints.instance.flutterToEngine('password'));
@@ -1729,7 +1731,7 @@ void testMain() {
           ['zzyyxx', 'aabbcc', 'jjkkll']);
       final EngineAutofillForm autofillForm =
           EngineAutofillForm.fromFrameworkMessage(
-              createAutofillInfo('username', 'field1'), fields);
+              createAutofillInfo('username', 'field1'), fields)!;
 
       expect(autofillForm.formIdentifier, 'aabbcc*jjkkll*zzyyxx');
     });
@@ -1742,7 +1744,7 @@ void testMain() {
           ['field1', 'fields2', 'field3']);
       final EngineAutofillForm autofillForm =
           EngineAutofillForm.fromFrameworkMessage(
-              createAutofillInfo('username', 'field1'), fields);
+              createAutofillInfo('username', 'field1'), fields)!;
 
       final InputElement testInputElement = InputElement();
       autofillForm.placeForm(testInputElement);
@@ -1752,7 +1754,7 @@ void testMain() {
       final FormElement form = autofillForm.formElement;
       expect(form.childNodes, hasLength(4));
 
-      final FormElement formOnDom = defaultTextEditingRoot.querySelector('form');
+      final FormElement formOnDom = defaultTextEditingRoot.querySelector('form') as FormElement;
       // Form is attached to the DOM.
       expect(form, equals(formOnDom));
 
@@ -1765,7 +1767,7 @@ void testMain() {
       final List<dynamic> fields = createFieldValues(['username'], ['field1']);
       final EngineAutofillForm autofillForm =
           EngineAutofillForm.fromFrameworkMessage(
-              createAutofillInfo('username', 'field1'), fields);
+              createAutofillInfo('username', 'field1'), fields)!;
 
       // The focused element is the only field. Form should be empty after
       // the initialization (focus element is appended later).
@@ -1776,7 +1778,7 @@ void testMain() {
       final FormElement form = autofillForm.formElement;
       // Submit button is added to the form.
       expect(form.childNodes, isNotEmpty);
-      final InputElement inputElement = form.childNodes.first;
+      final InputElement inputElement = form.childNodes.first as InputElement;
       expect(inputElement.type, 'submit');
 
       // The submit button should have class `submitBtn`.
@@ -1785,7 +1787,7 @@ void testMain() {
 
     test('Return null if no focused element', () {
       final List<dynamic> fields = createFieldValues(['username'], ['field1']);
-      final EngineAutofillForm autofillForm =
+      final EngineAutofillForm? autofillForm =
           EngineAutofillForm.fromFrameworkMessage(null, fields);
 
       expect(autofillForm, isNull);
@@ -1877,7 +1879,7 @@ void testMain() {
     setUp(() {
       editingStrategy =
           GloballyPositionedTextEditingStrategy(HybridTextEditing());
-      editingStrategy.enable(
+      editingStrategy!.enable(
         singlelineConfig,
         onChange: trackEditingState,
         onAction: trackInputAction,
@@ -1903,7 +1905,7 @@ void testMain() {
     });
 
     test('Configure input element from the editing state', () {
-      final InputElement input = defaultTextEditingRoot.querySelector('input');
+      final InputElement input = defaultTextEditingRoot.querySelector('input') as InputElement;
       _editingState =
           EditingState(text: 'Test', baseOffset: 1, extentOffset: 2);
 
@@ -1916,14 +1918,14 @@ void testMain() {
 
     test('Configure text area element from the editing state', () {
       cleanTextEditingStrategy();
-      editingStrategy.enable(
+      editingStrategy!.enable(
         multilineConfig,
         onChange: trackEditingState,
         onAction: trackInputAction,
       );
 
       final TextAreaElement textArea =
-          defaultTextEditingRoot.querySelector('textarea');
+          defaultTextEditingRoot.querySelector('textarea') as TextAreaElement;
       _editingState =
           EditingState(text: 'Test', baseOffset: 1, extentOffset: 2);
 
@@ -1935,7 +1937,7 @@ void testMain() {
     });
 
     test('Get Editing State from input element', () {
-      final InputElement input = defaultTextEditingRoot.querySelector('input');
+      final InputElement input = defaultTextEditingRoot.querySelector('input') as InputElement;
       input.value = 'Test';
       input.selectionStart = 1;
       input.selectionEnd = 2;
@@ -1949,13 +1951,13 @@ void testMain() {
 
     test('Get Editing State from text area element', () {
       cleanTextEditingStrategy();
-      editingStrategy.enable(
+      editingStrategy!.enable(
         multilineConfig,
         onChange: trackEditingState,
         onAction: trackInputAction,
       );
 
-      final TextAreaElement input = defaultTextEditingRoot.querySelector('textarea');
+      final TextAreaElement input = defaultTextEditingRoot.querySelector('textarea') as TextAreaElement;
       input.value = 'Test';
       input.selectionStart = 1;
       input.selectionEnd = 2;
@@ -1968,7 +1970,7 @@ void testMain() {
     });
 
     test('Compare two editing states', () {
-      final InputElement input = defaultTextEditingRoot.querySelector('input');
+      final InputElement input = defaultTextEditingRoot.querySelector('input') as InputElement;
       input.value = 'Test';
       input.selectionStart = 1;
       input.selectionEnd = 2;
@@ -1989,7 +1991,7 @@ void testMain() {
 KeyboardEvent dispatchKeyboardEvent(
   EventTarget target,
   String type, {
-  int keyCode,
+  required int keyCode,
 }) {
   final Function jsKeyboardEvent = js_util.getProperty(window, 'KeyboardEvent');
   final List<dynamic> eventArgs = <dynamic>[
@@ -2007,7 +2009,7 @@ KeyboardEvent dispatchKeyboardEvent(
 }
 
 MethodCall configureSetStyleMethodCall(int fontSize, String fontFamily,
-    int textAlignIndex, int fontWeightIndex, int textDirectionIndex) {
+    int textAlignIndex, int? fontWeightIndex, int textDirectionIndex) {
   return MethodCall('TextInput.setStyle', <String, dynamic>{
     'fontSize': fontSize,
     'fontFamily': fontFamily,
@@ -2029,9 +2031,9 @@ MethodCall configureSetSizeAndTransformMethodCall(
 /// Will disable editing element which will also clean the backup DOM
 /// element from the page.
 void cleanTextEditingStrategy() {
-  if (editingStrategy != null && editingStrategy.isEnabled) {
+  if (editingStrategy != null && editingStrategy!.isEnabled) {
     // Clean up all the DOM elements and event listeners.
-    editingStrategy.disable();
+    editingStrategy!.disable();
   }
 }
 
@@ -2041,7 +2043,10 @@ void cleanTestFlags() {
 }
 
 void checkInputEditingState(
-    InputElement input, String text, int start, int end) {
+    Element? element, String text, int start, int end) {
+  expect(element, isNotNull);
+  expect(element, isA<InputElement>());
+  final InputElement input = element as InputElement;
   expect(defaultTextEditingRoot.activeElement, input);
   expect(input.value, text);
   expect(input.selectionStart, start);
@@ -2082,9 +2087,9 @@ Map<String, dynamic> createFlutterConfig(
   bool obscureText = false,
   bool autocorrect = true,
   String textCapitalization = 'TextCapitalization.none',
-  String inputAction,
-  String autofillHint,
-  List<String> autofillHintsForFields,
+  String? inputAction,
+  String? autofillHint,
+  List<String>? autofillHintsForFields,
   bool decimal = false,
 }) {
   return <String, dynamic>{
diff --git a/engine/src/flutter/web_sdk/web_engine_tester/pubspec.yaml b/engine/src/flutter/web_sdk/web_engine_tester/pubspec.yaml
index 8ecd8befeea..12482e7ddab 100644
--- a/engine/src/flutter/web_sdk/web_engine_tester/pubspec.yaml
+++ b/engine/src/flutter/web_sdk/web_engine_tester/pubspec.yaml
@@ -6,7 +6,7 @@ environment:
 dependencies:
   js: 0.6.3
   stream_channel: 2.1.0
-  test: 1.16.6
+  test: 1.17.7
   webkit_inspection_protocol: 1.0.0
   ui:
     path: ../../lib/web_ui