WidgetController.startGesture trackpad support (#114631)

packages/flutter_test/lib/src/controller.dart

@@ -1086,12 +1086,14 @@ abstract class WidgetController {
     );
   }
 
-  /// Creates a gesture with an initial down gesture at a particular point, and
-  /// returns the [TestGesture] object which you can use to continue the
-  /// gesture.
+  /// Creates a gesture with an initial appropriate starting gesture at a
+  /// particular point, and returns the [TestGesture] object which you can use
+  /// to continue the gesture. Usually, the starting gesture will be a down event,
+  /// but if [kind] is set to [PointerDeviceKind.trackpad], the gesture will start
+  /// with a panZoomStart gesture.
   ///
   /// You can use [createGesture] if your gesture doesn't begin with an initial
-  /// down gesture.
+  /// down or panZoomStart gesture.
   ///
   /// See also:
   ///  * [WidgetController.drag], a method to simulate a drag.
@@ -1110,7 +1112,11 @@ abstract class WidgetController {
       kind: kind,
       buttons: buttons,
     );
-    await result.down(downLocation);
+    if (kind == PointerDeviceKind.trackpad) {
+      await result.panZoomStart(downLocation);
+    } else {
+      await result.down(downLocation);
+    }
     return result;
   }
 

packages/flutter_test/lib/src/test_pointer.dart

@@ -455,6 +455,7 @@ class TestGesture {
   /// Dispatch a pointer down event at the given `downLocation`, caching the
   /// hit test result.
   Future<void> down(Offset downLocation, { Duration timeStamp = Duration.zero }) async {
+    assert(_pointer.kind != PointerDeviceKind.trackpad, 'Trackpads are expected to send panZoomStart events, not down events.');
     return TestAsyncUtils.guard<void>(() async {
       return _dispatcher(_pointer.down(downLocation, timeStamp: timeStamp));
     });
@@ -463,6 +464,7 @@ class TestGesture {
   /// Dispatch a pointer down event at the given `downLocation`, caching the
   /// hit test result with a custom down event.
   Future<void> downWithCustomEvent(Offset downLocation, PointerDownEvent event) async {
+    assert(_pointer.kind != PointerDeviceKind.trackpad, 'Trackpads are expected to send panZoomStart events, not down events');
     _pointer.setDownInfo(event, downLocation);
     return TestAsyncUtils.guard<void>(() async {
       return _dispatcher(event);
@@ -507,7 +509,15 @@ class TestGesture {
   ///  * [WidgetController.fling], a method to simulate a fling.
   Future<void> moveBy(Offset offset, { Duration timeStamp = Duration.zero }) {
     assert(_pointer.location != null);
-    return moveTo(_pointer.location! + offset, timeStamp: timeStamp);
+    if (_pointer.isPanZoomActive) {
+      return panZoomUpdate(
+        _pointer.location!,
+        pan: (_pointer.pan ?? Offset.zero) + offset,
+        timeStamp: timeStamp
+      );
+    } else {
+      return moveTo(_pointer.location! + offset, timeStamp: timeStamp);
+    }
   }
 
   /// Send a move event moving the pointer to the given location.
@@ -521,6 +531,7 @@ class TestGesture {
   ///    It sends move events at a given frequency and it is useful when there are listeners involved.
   ///  * [WidgetController.fling], a method to simulate a fling.
   Future<void> moveTo(Offset location, { Duration timeStamp = Duration.zero }) {
+    assert(_pointer.kind != PointerDeviceKind.trackpad);
     return TestAsyncUtils.guard<void>(() {
       if (_pointer._isDown) {
         return _dispatcher(_pointer.move(location, timeStamp: timeStamp));
@@ -530,12 +541,19 @@ class TestGesture {
     });
   }
 
-  /// End the gesture by releasing the pointer.
+  /// End the gesture by releasing the pointer. For trackpad pointers this
+  /// will send a panZoomEnd event instead of an up event.
   Future<void> up({ Duration timeStamp = Duration.zero }) {
     return TestAsyncUtils.guard<void>(() async {
-      assert(_pointer._isDown);
-      await _dispatcher(_pointer.up(timeStamp: timeStamp));
-      assert(!_pointer._isDown);
+      if (_pointer.kind == PointerDeviceKind.trackpad) {
+        assert(_pointer._isPanZoomActive);
+        await _dispatcher(_pointer.panZoomEnd(timeStamp: timeStamp));
+        assert(!_pointer._isPanZoomActive);
+      } else {
+        assert(_pointer._isDown);
+        await _dispatcher(_pointer.up(timeStamp: timeStamp));
+        assert(!_pointer._isDown);
+      }
     });
   }
 
@@ -543,6 +561,7 @@ class TestGesture {
   /// system showed a modal dialog on top of the Flutter application,
   /// for instance).
   Future<void> cancel({ Duration timeStamp = Duration.zero }) {
+    assert(_pointer.kind != PointerDeviceKind.trackpad, 'Trackpads do not send cancel events.');
     return TestAsyncUtils.guard<void>(() async {
       assert(_pointer._isDown);
       await _dispatcher(_pointer.cancel(timeStamp: timeStamp));
@@ -553,6 +572,7 @@ class TestGesture {
   /// Dispatch a pointer pan zoom start event at the given `location`, caching the
   /// hit test result.
   Future<void> panZoomStart(Offset location, { Duration timeStamp = Duration.zero }) async {
+    assert(_pointer.kind == PointerDeviceKind.trackpad, 'Only trackpads can send PointerPanZoom events.');
     return TestAsyncUtils.guard<void>(() async {
       return _dispatcher(_pointer.panZoomStart(location, timeStamp: timeStamp));
     });
@@ -566,6 +586,7 @@ class TestGesture {
     double rotation = 0,
     Duration timeStamp = Duration.zero
   }) async {
+    assert(_pointer.kind == PointerDeviceKind.trackpad, 'Only trackpads can send PointerPanZoom events.');
     return TestAsyncUtils.guard<void>(() async {
       return _dispatcher(_pointer.panZoomUpdate(location,
         pan: pan,
@@ -580,6 +601,7 @@ class TestGesture {
   Future<void> panZoomEnd({
     Duration timeStamp = Duration.zero
   }) async {
+    assert(_pointer.kind == PointerDeviceKind.trackpad, 'Only trackpads can send PointerPanZoom events.');
     return TestAsyncUtils.guard<void>(() async {
       return _dispatcher(_pointer.panZoomEnd(
         timeStamp: timeStamp

packages/flutter_test/test/controller_test.dart

@@ -385,6 +385,40 @@ void main() {
     },
   );
 
+  testWidgets(
+    'WidgetTester.drag works with trackpad kind',
+    (WidgetTester tester) async {
+      final List<String> logs = <String>[];
+
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: Listener(
+            onPointerDown: (PointerDownEvent event) => logs.add('down ${event.buttons}'),
+            onPointerMove: (PointerMoveEvent event) => logs.add('move ${event.buttons}'),
+            onPointerUp: (PointerUpEvent event) => logs.add('up ${event.buttons}'),
+            onPointerPanZoomStart: (PointerPanZoomStartEvent event) => logs.add('panZoomStart'),
+            onPointerPanZoomUpdate: (PointerPanZoomUpdateEvent event) => logs.add('panZoomUpdate ${event.pan}'),
+            onPointerPanZoomEnd: (PointerPanZoomEndEvent event) => logs.add('panZoomEnd'),
+            child: const Text('test'),
+          ),
+        ),
+      );
+
+      await tester.drag(find.text('test'), const Offset(-150.0, 200.0), kind: PointerDeviceKind.trackpad);
+
+      for(int i = 0; i < logs.length; i++) {
+        if (i == 0) {
+          expect(logs[i], 'panZoomStart');
+        } else if (i != logs.length - 1) {
+          expect(logs[i], startsWith('panZoomUpdate'));
+        } else {
+          expect(logs[i], 'panZoomEnd');
+        }
+      }
+    },
+  );
+
   testWidgets(
     'WidgetTester.fling must respect buttons',
     (WidgetTester tester) async {