test: eraser path widget guard (device-independent)

A stylus pass through a committed stroke in eraser mode fires onEraseStroke for it; a pass far from any stroke erases nothing. Locks in the eraser path (the user reported eraser reliability issues) as a regression guard without a device. flutter analyze lib/editor clean; 237/237 tests (+2). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-23 03:48:33 +08:00
parent c8579d3e86
commit 84d7dc8d24
1 changed files with 101 additions and 0 deletions
--- a/test/pen_eraser_widget_test.dart
+++ b/test/pen_eraser_widget_test.dart
@@ -0,0 +1,101 @@
+// Device-independent widget test of the eraser path (the user reported eraser
+// reliability issues). A stylus drag through a committed stroke in eraser mode
+// must fire onEraseStroke for that stroke.
+
+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:badnote/editor/canvas/pen_canvas.dart';
+import 'package:badnote/editor/canvas/pen_stroke.dart';
+
+void main() {
+  const pageSize = Size(400, 600);
+
+  // A horizontal stroke through the normalized center (0.5, 0.5).
+  PenStroke centerStroke() => PenStroke(
+        points: const [
+          PenPoint(0.4, 0.5, 0.5),
+          PenPoint(0.5, 0.5, 0.5),
+          PenPoint(0.6, 0.5, 0.5),
+        ],
+        color: 0xFF000000,
+        width: 0.004,
+        kind: PenStrokeKind.pen,
+      );
+
+  Widget host({
+    required List<PenStroke> strokes,
+    required void Function(int, List<PenStroke>) onErase,
+    required TransformationController controller,
+  }) =>
+      MaterialApp(
+        home: Scaffold(
+          body: Center(
+            child: SizedBox(
+              width: pageSize.width,
+              height: pageSize.height,
+              child: PenCanvas(
+                pageWidget: Container(color: const Color(0xFFEEEEEE)),
+                pageSize: pageSize,
+                strokes: strokes,
+                transformationController: controller,
+                tool: CanvasTool.eraser,
+                color: const Color(0xFF000000),
+                strokeWidth: 0.004,
+                onStrokeComplete: (_) {},
+                onEraseStroke: onErase,
+              ),
+            ),
+          ),
+        ),
+      );
+
+  testWidgets('eraser tool: a stylus pass over a stroke fires onEraseStroke',
+      (tester) async {
+    final erased = <int>[];
+    final controller = TransformationController();
+    addTearDown(controller.dispose);
+
+    await tester.pumpWidget(host(
+      strokes: [centerStroke()],
+      onErase: (i, _) => erased.add(i),
+      controller: controller,
+    ));
+
+    // Drag a stylus vertically through the screen center (= normalized 0.5,0.5,
+    // where the stroke sits).
+    final center = tester.getCenter(find.byType(PenCanvas));
+    final g = await tester.startGesture(center + const Offset(0, -20),
+        kind: PointerDeviceKind.stylus);
+    await g.moveBy(const Offset(0, 20));
+    await g.moveBy(const Offset(0, 20));
+    await g.up();
+    await tester.pump();
+
+    expect(erased, contains(0), reason: 'the center stroke should be erased');
+  });
+
+  testWidgets('eraser tool: a pass far from any stroke erases nothing',
+      (tester) async {
+    final erased = <int>[];
+    final controller = TransformationController();
+    addTearDown(controller.dispose);
+
+    await tester.pumpWidget(host(
+      strokes: [centerStroke()],
+      onErase: (i, _) => erased.add(i),
+      controller: controller,
+    ));
+
+    // Drag in the top-left corner, far from the centered stroke.
+    final topLeft = tester.getTopLeft(find.byType(PenCanvas));
+    final g = await tester.startGesture(topLeft + const Offset(10, 10),
+        kind: PointerDeviceKind.stylus);
+    await g.moveBy(const Offset(5, 5));
+    await g.up();
+    await tester.pump();
+
+    expect(erased, isEmpty);
+  });
+}