fix out of range error in end index

flutter · Feb 15, 2024 · 1e68532 · 1e68532
1 parent 8743183
commit 1e68532
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Showing 2 changed files with 14 additions and 3 deletions.
diff --git a/packages/flutter_test/lib/src/controller.dart b/packages/flutter_test/lib/src/controller.dart
@@ -289,7 +289,7 @@ class SemanticsController {
         'Traversal: [\n  ${traversal.join('\n  ')}\n]');
     }
 
-    int endIndex;
+    int? endIndex;
     if (end != null) {
       node = find(end);
       endIndex = traversal.indexOf(node);
@@ -298,8 +298,6 @@ class SemanticsController {
       node = endNode.evaluate().single;
       endIndex = traversal.indexOf(node);
       errorString = endNode.toString(describeSelf: true);
-    } else {
-      endIndex = traversal.length - 1;
     }
     if (endIndex == -1) {
       throw StateError(
@@ -308,6 +306,7 @@ class SemanticsController {
         'Expected End Node: $node\n\n'
         'Traversal: [\n  ${traversal.join('\n  ')}\n]');
     }
+    endIndex ??= traversal.length - 1;
 
     return traversal.getRange(startIndex, endIndex + 1);
   }

diff --git a/packages/flutter_test/test/controller_test.dart b/packages/flutter_test/test/controller_test.dart
@@ -920,6 +920,18 @@ void main() {
           orderedEquals(expectedMatchers));
       });
 
+      testWidgets('simulatedAccessibilityTraversal end Index supports empty traversal', (WidgetTester tester) async {
+        await tester.pumpWidget(const MaterialApp(
+          home: Center(
+            child: Column(), // No nodes!
+          ),
+        ));
+        expect(
+          tester.semantics.simulatedAccessibilityTraversal().map((SemanticsNode node) => node.label),
+          <String>[],
+        );
+      });
+
       testWidgets('starts traversal at semantics node for `startNode`', (WidgetTester tester) async {
         await tester.pumpWidget(MaterialApp(
           home: Center(