CEC-5182: add car update status to fleet (#466)

src/utils/polling.test.js

@@ -0,0 +1,31 @@
+import Polling from "./polling";
+
+function sleep(ms) {
+  return new Promise(resolve => setTimeout(resolve, ms));
+}
+
+describe("Polling", () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it("starts and ends polling", async () => {
+    const callback = () => Promise.resolve();
+    const poll = new Polling(callback, 100);
+    const spy = jest.spyOn(poll, "callback");
+    poll.start();
+    await sleep(500);
+    poll.end();
+    await sleep(500);
+    expect(spy).toHaveBeenCalledTimes(5);
+  });
+
+  it("async polling", async () => {
+    const callback = () => sleep(100);
+    const poll = new Polling(callback, 100);
+    const spy = jest.spyOn(poll, "callback");
+    poll.start();
+    await sleep(1000);
+    expect(spy).toHaveBeenCalledTimes(5);
+  });
+});