Organize tests

test/browser/spec/util.js

@@ -0,0 +1,16 @@
+export function overrideRAF() {
+  const raf = window.requestAnimationFrame;
+  const caf = window.cancelAnimationFrame;
+
+  window.requestAnimationFrame = function (callback) {
+    return setTimeout(callback, 1);
+  };
+  window.cancelAnimationFrame = function (key) {
+    return clearTimeout(key);
+  };
+
+  return function () {
+    window.requestAnimationFrame = raf;
+    window.cancelAnimationFrame = caf;
+  };
+}