Add test for interactive_viewer.constrained.0.dart (#158044)

Contributes to flutter/flutter#130459

It adds a test for
- `examples/api/lib/widgets/interactive_viewer/interactive_viewer.constrained.0.dart`

Author: ValentinVignal

dev/bots/check_code_samples.dart

@@ -316,5 +316,4 @@ final Set<String> _knownMissingTests = <String>{
   'examples/api/test/widgets/scrollbar/raw_scrollbar.2_test.dart',
   'examples/api/test/widgets/scrollbar/raw_scrollbar.desktop.0_test.dart',
   'examples/api/test/widgets/scrollbar/raw_scrollbar.shape.0_test.dart',
-  'examples/api/test/widgets/interactive_viewer/interactive_viewer.constrained.0_test.dart',
 };

examples/api/test/widgets/interactive_viewer/interactive_viewer.constrained.0_test.dart

@@ -0,0 +1,79 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/widgets/interactive_viewer/interactive_viewer.constrained.0.dart'
+    as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('The reset button resets the view with an animation', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const example.ConstrainedExampleApp(),
+    );
+
+    expect(find.widgetWithText(AppBar, 'Constrained Sample'), findsOne);
+    expect(find.byType(InteractiveViewer), findsOne);
+    for (int row = 0; row < 48; row += 1) {
+      for (int column = 0; column < 6; column += 1) {
+        expect(find.text('$row x $column'), findsOne);
+      }
+    }
+    expect(
+      tester.getRect(find.byType(Table)),
+      rectMoreOrLessEquals(const Rect.fromLTRB(0.0, 56.0, 1200.0, 1304.0)),
+    );
+
+    // Pans along the x axis.
+    const Offset panStart = Offset(400.0, 300.0);
+    final Offset panXEnd = panStart - const Offset(0, 20);
+    final TestGesture gesturePanX = await tester.startGesture(panStart);
+    await tester.pump();
+    await gesturePanX.moveTo(panXEnd);
+    await tester.pump();
+    await gesturePanX.up();
+    await tester.pumpAndSettle();
+
+    expect(
+      tester.getRect(find.byType(Table)),
+      rectMoreOrLessEquals(const Rect.fromLTRB(0.0, 36.0, 1200.0, 1284.0)),
+    );
+
+    // Pans along the Y axis.
+    final Offset panYEnd = panStart - const Offset(20, 0);
+    final TestGesture gesturePanY = await tester.startGesture(panStart);
+    await tester.pump();
+    await gesturePanY.moveTo(panYEnd);
+    await tester.pump();
+    await gesturePanY.up();
+    await tester.pumpAndSettle();
+
+    expect(
+      tester.getRect(find.byType(Table)),
+      rectMoreOrLessEquals(const Rect.fromLTRB(-20.0, 36.0, 1180.0, 1284.0)),
+    );
+
+    // Tries to zooms even if it is disabled.
+    const Offset scaleStart1 = Offset(400.0, 300.0);
+    final Offset scaleStart2 = scaleStart1 + const Offset(10.0, 0.0);
+    final Offset scaleEnd1 = scaleStart1 - const Offset(10.0, 0.0);
+    final Offset scaleEnd2 = scaleStart2 + const Offset(10.0, 0.0);
+    final TestGesture gesture1 = await tester.createGesture();
+    final TestGesture gesture2 = await tester.createGesture();
+    await gesture1.down(scaleStart1);
+    await gesture2.down(scaleStart2);
+    await tester.pump();
+    await gesture1.moveTo(scaleEnd1);
+    await gesture2.moveTo(scaleEnd2);
+    await tester.pump();
+    await gesture1.up();
+    await gesture2.up();
+    await tester.pumpAndSettle();
+
+    expect(
+      tester.getRect(find.byType(Table)),
+      rectMoreOrLessEquals(const Rect.fromLTRB(-20.0, 36.0, 1180.0, 1284.0)),
+    );
+  });
+}