From 2ea212dbdf36bbb32bc35edb10cd9df69cedd8c1 Mon Sep 17 00:00:00 2001
From: Angelo Silvestre <angelosilvestre.ccp@gmail.com>
Date: Mon, 8 Jan 2024 16:38:12 -0300
Subject: [PATCH] Create a WidgetTester extension to drag scroll bars (Resolves
 #22)

---
 lib/flutter_test_robots.dart |  1 +
 lib/src/scrollbar.dart       | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 lib/src/scrollbar.dart

diff --git a/lib/flutter_test_robots.dart b/lib/flutter_test_robots.dart
index e5afbf7..b8b3380 100644
--- a/lib/flutter_test_robots.dart
+++ b/lib/flutter_test_robots.dart
@@ -3,3 +3,4 @@ library flutter_test_robots;
 export 'src/clipboard.dart';
 export 'src/input_method_engine.dart';
 export 'src/keyboard.dart';
+export 'src/scrollbar.dart';
diff --git a/lib/src/scrollbar.dart b/lib/src/scrollbar.dart
new file mode 100644
index 0000000..01f7722
--- /dev/null
+++ b/lib/src/scrollbar.dart
@@ -0,0 +1,26 @@
+import 'package:flutter/gestures.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+/// Simulates the user interacting with a Scrollbar.
+extension ScrollbarInteractions on WidgetTester {
+  /// Press a scrollbar thumb at [thumbLocation] and drag it vertically by [delta] pixels.
+  Future<void> dragScrollbar(Offset thumbLocation, double delta) async {
+    //Hover to make the thumb visible with a duration long enough to run the fade in animation.
+    final testPointer = TestPointer(1, PointerDeviceKind.mouse);
+
+    await sendEventToBinding(testPointer.hover(thumbLocation, timeStamp: const Duration(seconds: 1)));
+    await pumpAndSettle();
+
+    // Press the thumb.
+    await sendEventToBinding(testPointer.down(thumbLocation));
+    await pump(const Duration(milliseconds: 40));
+
+    // Move the thumb down.
+    await sendEventToBinding(testPointer.move(thumbLocation + Offset(0, delta)));
+    await pump();
+
+    // Release the pointer.
+    await sendEventToBinding(testPointer.up());
+    await pump();
+  }
+}