Test via defaultPrevented and manually dispatching events

Author: justinmc

lib/web_ui/lib/src/engine/view_embedder/embedding_strategy/embedding_strategy.dart

@@ -60,8 +60,7 @@ abstract class EmbeddingStrategy with _ContextMenu {
 
 mixin _ContextMenu {
   /// False when the context menu has been disabled, otherwise true.
-  @visibleForTesting
-  bool contextMenuEnabled = true;
+  bool _contextMenuEnabled = true;
 
   /// Listener for contextmenu events that prevents the browser's context menu
   /// from being shown.
@@ -89,12 +88,13 @@ mixin _ContextMenu {
   ///    [DomElement].
   @protected
   void disableContextMenuOn(DomElement element) {
-    if (!contextMenuEnabled) {
+    if (!_contextMenuEnabled) {
       return;
     }
 
+    print('justin disabling');
     element.addEventListener('contextmenu', _disablingContextMenuListener);
-    contextMenuEnabled = false;
+    _contextMenuEnabled = false;
   }
 
   /// Enables the browser's context menu for this part of the DOM.
@@ -117,11 +117,11 @@ mixin _ContextMenu {
   ///    [DomElement].
   @protected
   void enableContextMenuOn(DomElement element) {
-    if (contextMenuEnabled) {
+    if (_contextMenuEnabled) {
       return;
     }
 
     element.removeEventListener('contextmenu', _disablingContextMenuListener);
-    contextMenuEnabled = true;
+    _contextMenuEnabled = true;
   }
 }

lib/web_ui/test/engine/view_embedder/embedding_strategy/custom_element_embedding_strategy_test.dart

@@ -7,6 +7,7 @@
 import 'package:test/bootstrap/browser.dart';
 import 'package:test/test.dart';
 import 'package:ui/src/engine/dom.dart';
+import 'package:ui/src/engine/safe_browser_api.dart';
 import 'package:ui/src/engine/view_embedder/embedding_strategy/custom_element_embedding_strategy.dart';
 
 void main() {
@@ -135,19 +136,40 @@ void doTests() {
     });
 
     test('disableContextMenu and enableContextMenu can toggle the context menu', () {
-      expect(strategy.contextMenuEnabled, isTrue);
+      // When the app starts, contextmenu events are not prevented.
+      DomEvent event = createDomEvent('Event', 'contextmenu');
+      expect(event.defaultPrevented, isFalse);
+      target.dispatchEvent(event);
+      expect(event.defaultPrevented, isFalse);
 
+      // Disabling the context menu causes contextmenu events to be prevented.
       strategy.disableContextMenu();
-      expect(strategy.contextMenuEnabled, isFalse);
+      event = createDomEvent('Event', 'contextmenu');
+      expect(event.defaultPrevented, isFalse);
+      target.dispatchEvent(event);
+      expect(event.defaultPrevented, isTrue);
 
+      // Disabling again has no effect.
       strategy.disableContextMenu();
-      expect(strategy.contextMenuEnabled, isFalse);
+      event = createDomEvent('Event', 'contextmenu');
+      expect(event.defaultPrevented, isFalse);
+      target.dispatchEvent(event);
+      expect(event.defaultPrevented, isTrue);
 
+      // Enabling the context menu means that contextmenu events are back to not
+      // being prevented.
       strategy.enableContextMenu();
-      expect(strategy.contextMenuEnabled, isTrue);
+      event = createDomEvent('Event', 'contextmenu');
+      expect(event.defaultPrevented, isFalse);
+      target.dispatchEvent(event);
+      expect(event.defaultPrevented, isFalse);
 
+      // Enabling again has no effect.
       strategy.enableContextMenu();
-      expect(strategy.contextMenuEnabled, isTrue);
+      event = createDomEvent('Event', 'contextmenu');
+      expect(event.defaultPrevented, isFalse);
+      target.dispatchEvent(event);
+      expect(event.defaultPrevented, isFalse);
     });
   });
 }

lib/web_ui/test/engine/view_embedder/embedding_strategy/full_page_embedding_strategy_test.dart

@@ -131,22 +131,48 @@ void doTests() {
   });
 
   group('context menu', () {
+    setUp(() {
+      strategy = FullPageEmbeddingStrategy();
+      strategy.initialize();
+    });
+
     test('disableContextMenu and enableContextMenu can toggle the context menu', () {
       final FullPageEmbeddingStrategy strategy = FullPageEmbeddingStrategy();
 
-      expect(strategy.contextMenuEnabled, isTrue);
+      // When the app starts, contextmenu events are not prevented.
+      DomEvent event = createDomEvent('Event', 'contextmenu');
+      expect(event.defaultPrevented, isFalse);
+      target.dispatchEvent(event);
+      expect(event.defaultPrevented, isFalse);
 
+      // Disabling the context menu causes contextmenu events to be prevented.
       strategy.disableContextMenu();
-      expect(strategy.contextMenuEnabled, isFalse);
+      event = createDomEvent('Event', 'contextmenu');
+      expect(event.defaultPrevented, isFalse);
+      target.dispatchEvent(event);
+      expect(event.defaultPrevented, isTrue);
 
+      // Disabling again has no effect.
       strategy.disableContextMenu();
-      expect(strategy.contextMenuEnabled, isFalse);
+      event = createDomEvent('Event', 'contextmenu');
+      expect(event.defaultPrevented, isFalse);
+      target.dispatchEvent(event);
+      expect(event.defaultPrevented, isTrue);
 
+      // Enabling the context menu means that contextmenu events are back to not
+      // being prevented.
       strategy.enableContextMenu();
-      expect(strategy.contextMenuEnabled, isTrue);
+      event = createDomEvent('Event', 'contextmenu');
+      expect(event.defaultPrevented, isFalse);
+      target.dispatchEvent(event);
+      expect(event.defaultPrevented, isFalse);
 
+      // Enabling again has no effect.
       strategy.enableContextMenu();
-      expect(strategy.contextMenuEnabled, isTrue);
+      event = createDomEvent('Event', 'contextmenu');
+      expect(event.defaultPrevented, isFalse);
+      target.dispatchEvent(event);
+      expect(event.defaultPrevented, isFalse);
     });
   });
 }