test: Use transitionDurationObserver in action_sheet_test

Replaces hardcoded transition delays with dynamic duration handling
via transitionDurationObserver.pumpPastTransition(tester). This
ensures test stability when transition timings change.
additionally added pumpAndSettle to wait for snackbar to show.
attached TransitionDurationObserver through navigatorObservers in test
widgets to dynamically track transition durations. Prepares tests for
replacement of static pump durations.

Author: MdSaifAliMolla

test/widgets/action_sheet_test.dart

@@ -140,7 +140,7 @@ Future<void> setupToMessageActionSheet(WidgetTester tester, {
   // like if it's in padding around a Paragraph.
   await tester.longPress(find.byType(MessageContent), warnIfMissed: false);
   // sheet appears onscreen; default duration of bottom-sheet enter animation
-  await tester.pump(const Duration(milliseconds: 250));
+  await transitionDurationObserver.pumpPastTransition(tester);
   // Check the action sheet did in fact open, so we don't defeat any tests that
   // use simple `find.byIcon`-style checks to test presence/absence of a button.
   check(find.byType(BottomSheet)).findsOne();
@@ -199,26 +199,29 @@ void main() {
       check(find.byType(InboxPageBody)).findsOne();
 
       await tester.longPress(find.text(someChannel.name).hitTestable());
-      await tester.pump(const Duration(milliseconds: 250));
+      await transitionDurationObserver.pumpPastTransition(tester);
     }
 
     Future<void> showFromSubscriptionList(WidgetTester tester) async {
+      transitionDurationObserver = TransitionDurationObserver();
       await tester.pumpWidget(TestZulipApp(accountId: eg.selfAccount.id,
+        navigatorObservers: [transitionDurationObserver],
         child: const HomePage()));
       await tester.pump();
       await tester.tap(find.byIcon(ZulipIcons.hash_italic));
       await tester.pump();
       check(find.byType(SubscriptionListPageBody)).findsOne();
 
       await tester.longPress(find.text(someChannel.name).hitTestable());
-      await tester.pump(const Duration(milliseconds: 250));
+      await transitionDurationObserver.pumpPastTransition(tester);
     }
 
     Future<void> showFromMsglistAppBar(WidgetTester tester, {
       ZulipStream? channel,
       required Narrow narrow,
     }) async {
       channel ??= someChannel;
+      transitionDurationObserver = TransitionDurationObserver();
 
       connection.prepare(json: eg.newestGetMessagesResult(
         foundOldest: true, messages: []).toJson());
@@ -229,31 +232,34 @@ void main() {
       }
       await tester.pumpWidget(TestZulipApp(
         accountId: eg.selfAccount.id,
+        navigatorObservers: [transitionDurationObserver],
         child: MessageListPage(
           initNarrow: narrow)));
       await tester.pumpAndSettle();
 
       await tester.longPress(find.descendant(
         of: find.byType(ZulipAppBar),
         matching: find.text(channel.name)));
-      await tester.pump(const Duration(milliseconds: 250));
+      await transitionDurationObserver.pumpPastTransition(tester);
     }
 
     Future<void> showFromRecipientHeader(WidgetTester tester, {
       StreamMessage? message,
     }) async {
       message ??= someMessage;
+      transitionDurationObserver = TransitionDurationObserver();
 
       connection.prepare(json: eg.newestGetMessagesResult(
         foundOldest: true, messages: [message]).toJson());
       await tester.pumpWidget(TestZulipApp(accountId: eg.selfAccount.id,
+        navigatorObservers: [transitionDurationObserver],
         child: const MessageListPage(initNarrow: CombinedFeedNarrow())));
       await tester.pumpAndSettle();
 
       await tester.longPress(find.descendant(
         of: find.byType(RecipientHeader),
         matching: find.text(message.displayRecipient ?? '')));
-      await tester.pump(const Duration(milliseconds: 250));
+      await transitionDurationObserver.pumpPastTransition(tester);
     }
 
     Future<void> showFromTopicListAppBar(WidgetTester tester, {int? streamId}) async {
@@ -739,7 +745,7 @@ void main() {
 
       await tester.longPress(find.text(topic));
       // sheet appears onscreen; default duration of bottom-sheet enter animation
-      await tester.pump(const Duration(milliseconds: 250));
+      await transitionDurationObserver.pumpPastTransition(tester);
     }
 
     Future<void> showFromAppBar(WidgetTester tester, {
@@ -766,7 +772,7 @@ void main() {
           effectiveTopic.displayName ?? eg.defaultRealmEmptyTopicDisplayName));
       await tester.longPress(topicRow);
       // sheet appears onscreen; default duration of bottom-sheet enter animation
-      await tester.pump(const Duration(milliseconds: 250));
+      await transitionDurationObserver.pumpPastTransition(tester);
     }
 
     Future<void> showFromRecipientHeader(WidgetTester tester, {
@@ -785,7 +791,7 @@ void main() {
         of: find.byType(RecipientHeader),
         matching: find.text(effectiveMessage.topic.displayName!)));
       // sheet appears onscreen; default duration of bottom-sheet enter animation
-      await tester.pump(const Duration(milliseconds: 250));
+      await transitionDurationObserver.pumpPastTransition(tester);
     }
 
     final actionSheetFinder = find.byType(BottomSheet);
@@ -2049,9 +2055,11 @@ void main() {
           delay: const Duration(milliseconds: 500));
         await tapCopyMessageTextButton(tester);
         // … and pump a frame to finish the NavigationState.pop animation…
-        await tester.pump(const Duration(milliseconds: 250));
+        await transitionDurationObserver.pumpPastTransition(tester);
         // … before the request finishes.  This is the repro condition for #732.
-        await tester.pump(const Duration(milliseconds: 250));
+        await transitionDurationObserver.pumpPastTransition(tester);
+        // …pump for snackbar to show
+        await tester.pumpAndSettle();
 
         final snackbar = tester.widget<SnackBar>(find.byType(SnackBar));
         check(snackbar.behavior).equals(SnackBarBehavior.floating);
@@ -2283,7 +2291,7 @@ void main() {
             // See comment in setupToMessageActionSheet about warnIfMissed: false
             await tester.longPress(find.byType(MessageContent), warnIfMissed: false);
             // sheet appears onscreen; default duration of bottom-sheet enter animation
-            await tester.pump(const Duration(milliseconds: 250));
+            await transitionDurationObserver.pumpPastTransition(tester);
             check(find.byType(BottomSheet)).findsOne();
             checkButtonIsPresent(expected);