Add integration tests

src/core/common/utils/animationFrame.ts

@@ -0,0 +1,4 @@
+/** A promisified animation frame. */
+export default function animationFrame() {
+  return new Promise(resolve => requestAnimationFrame(resolve));
+}

src/core/common/utils/index.ts

@@ -1,3 +1,4 @@
 export { default as timeout } from "./timeout";
+export { default as animationFrame } from "./animationFrame";
 export { default as pascalCase } from "./pascalCase";
 export { default as oncePerFrame } from "./oncePerFrame";