chore: add test for the T1260277 ticket

e2e/testcafe-devextreme/tests/common/eventsEngine.ts

@@ -0,0 +1,62 @@
+import { ClientFunction, Selector } from 'testcafe';
+import url from '../../helpers/getPageUrl';
+
+fixture.disablePageReloads`Events`
+  .page(url(__dirname, '../container.html'));
+
+const init = ClientFunction(() => {
+  const markup =
+  `<div class="dx-viewport demo-container">
+      <div id="draggable" draggable="true" style="width: 200px; height: 200px; background-color: red;"></div>
+      <div id="target" style="width: 200px; height: 200px; background-color: black;"></div>
+      <div>hoverStartTriggerCount</div>
+      <div id="hoverStartTriggerCount">0</div>
+      <div>hoverEndTriggerCount</div>
+      <div id="hoverEndTriggerCount">0</div>
+  </div>`;
+
+  $('#container').html(markup);
+
+  const { DevExpress } = (window as any);
+
+  let hoverStartTriggerCount = 0;
+  let hoverEndTriggerCount = 0;
+
+  DevExpress.events.on($("#target"), "dxhoverstart", () => {
+    hoverStartTriggerCount++;
+
+    $('#hoverStartTriggerCount').text(hoverStartTriggerCount);
+  });
+
+  DevExpress.events.on($("#target"), "dxhoverend", () => {
+      hoverEndTriggerCount++;
+
+      $('#hoverEndTriggerCount').text(hoverEndTriggerCount);
+  });
+});
+
+test('The `dxhoverstart` event should be triggered after dragging and dropping an HTML draggable element (T1260277)', async (t) => {
+  const draggable = Selector('#draggable');
+  const target = Selector('#target');
+  const hoverStartTriggerCount = Selector('#hoverStartTriggerCount');
+  const hoverEndTriggerCount = Selector('#hoverEndTriggerCount');
+
+  await t
+    .drag(draggable, 0, 400, { speed: 1 });
+
+  // `.drag` does not trigger the `pointercancel` event.
+  // A sequence of `.drag` calls behaves like a single drag&drop operation, and each call does not trigger the `pointerup` event.
+  // Even if it did, the `pointercancel` event would not be triggered as specified in:
+  // https://www.w3.org/TR/pointerevents/#suppressing-a-pointer-event-stream
+  // This is a hack to test the event engine's logic.
+  await t.dispatchEvent(draggable, 'pointercancel');
+
+  await t
+    .drag(target, 0, 400, { speed: 1 });
+
+  await t.expect(hoverStartTriggerCount.textContent).eql('1');
+  await t.expect(hoverEndTriggerCount.textContent).eql('1');
+
+}).before(async () => {
+  await init();
+});