Add tests for autoRetryOnRejection util

src/utils/promise/autoRetryOnRejection/index.test.ts

@@ -0,0 +1,91 @@
+import { autoRetryOnRejection } from '.';
+
+const aSuccessLoader = () => {
+  const result = { success: true };
+  const promise = Promise.resolve(result);
+  const loader = jest.fn(() => promise);
+
+  return {
+    result,
+    loader,
+  };
+};
+
+const anErrorThenSuccessLoader = () => {
+  const result = { success: true };
+  const error = new Error('Failed to load');
+  const resolvedPromise = Promise.resolve(result);
+  const rejectedPromise = Promise.reject(error);
+  const loader = jest.fn(() => resolvedPromise);
+
+  loader.mockReturnValueOnce(rejectedPromise);
+
+  return {
+    result,
+    error,
+    loader,
+  };
+};
+
+beforeEach(() => jest.useFakeTimers());
+
+it('does not auto-retry if the promise resolves the first time', async () => {
+  const { loader, result } = aSuccessLoader();
+
+  const promise = autoRetryOnRejection(loader);
+
+  const value = await promise;
+
+  expect(value).toBe(result);
+  expect(loader).toHaveBeenCalledTimes(1);
+});
+
+it('auto-retries if the promise rejects', async () => {
+  const { loader, result } = anErrorThenSuccessLoader();
+
+  const promise = autoRetryOnRejection(loader);
+
+  // Allow the loader promise to reject
+  await Promise.resolve();
+
+  jest.advanceTimersByTime(2000);
+
+  await Promise.resolve();
+
+  expect(loader).toHaveBeenCalledTimes(1);
+
+  jest.advanceTimersByTime(1000);
+
+  await Promise.resolve();
+
+  expect(loader).toHaveBeenCalledTimes(2);
+
+  const value = await promise;
+
+  expect(value).toBe(result);
+});
+
+it('auto-retries respecting the passed timeoutMs', async () => {
+  const { loader, result } = anErrorThenSuccessLoader();
+
+  const promise = autoRetryOnRejection(loader, { timeoutMs: 10000 });
+
+  // Allow the loader promise to reject and set the timer
+  await Promise.resolve();
+
+  jest.advanceTimersByTime(5000);
+
+  await Promise.resolve();
+
+  expect(loader).toHaveBeenCalledTimes(1);
+
+  jest.advanceTimersByTime(5000);
+
+  await Promise.resolve();
+
+  expect(loader).toHaveBeenCalledTimes(2);
+
+  const value = await promise;
+
+  expect(value).toBe(result);
+});