[Improvement] Slider: add test cases (#1192)

test/utils.js

@@ -0,0 +1,36 @@
+// Trigger pointer/touch event
+export function trigger(wrapper, eventName, x = 0, y = 0) {
+  const el = wrapper.element ? wrapper.element : wrapper;
+  const touch = {
+    identifier: Date.now(),
+    target: el,
+    pageX: x,
+    pageY: y,
+    clientX: x,
+    clientY: y,
+    radiusX: 2.5,
+    radiusY: 2.5,
+    rotationAngle: 10,
+    force: 0.5
+  };
+
+  const event = document.createEvent('CustomEvent');
+  event.initCustomEvent(eventName, true, true, {});
+  event.touches = [touch];
+  event.targetTouches = [touch];
+  event.changedTouches = [touch];
+  event.clientX = x;
+  event.clientY = y;
+
+  el.dispatchEvent(event);
+}
+
+// simulate drag gesture
+export function triggerDrag(el, x = 0, y = 0) {
+  trigger(el, 'touchstart', 0, 0);
+  trigger(el, 'touchmove', x / 4, y / 4);
+  trigger(el, 'touchmove', x / 3, y / 3);
+  trigger(el, 'touchmove', x / 2, y / 2);
+  trigger(el, 'touchmove', x, y);
+  trigger(el, 'touchend', x, y);
+}