99 lines
2.9 KiB
TypeScript
99 lines
2.9 KiB
TypeScript
import { withRetry } from "./retries";
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const FAST_RETRY_CONFIG: Parameters<typeof withRetry>[1] = {
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attempts: 6,
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// Always retry almost immediately, even when using real timers.
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backoffMs: () => 1,
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};
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test("successful function only executes once", async () => {
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const fn = jest.fn(async () => "success!");
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const result = await withRetry(fn, FAST_RETRY_CONFIG)();
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expect(result).toEqual("success!");
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expect(fn).toHaveBeenCalledTimes(1);
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});
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test("failing function rejects after correct number of attempts", async () => {
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const fn = jest.fn(async () => {
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throw "oops!";
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});
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await expect(withRetry(fn, FAST_RETRY_CONFIG)()).rejects.toEqual("oops!");
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expect(fn).toHaveBeenCalledTimes(FAST_RETRY_CONFIG.attempts);
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});
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test("parameters are passed through", async () => {
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const fn = async (str: string, n: number) => {
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let result = "";
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for (let i = 0; i < n; i += 1) {
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result += str;
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}
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return result;
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};
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const retriable = withRetry(fn, FAST_RETRY_CONFIG);
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// A bit of type system hackery to assert at build time that function
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// signatures match.
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/* eslint-disable @typescript-eslint/no-unused-vars */
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type Assert<_T extends true> = void;
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type _ = Assert<typeof retriable extends typeof fn ? true : false>;
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/* eslint-enable @typescript-eslint/no-unused-vars */
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await expect(retriable("hello;", 3)).resolves.toEqual("hello;hello;hello;");
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});
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test("retries back off with expected delays", async () => {
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jest.useFakeTimers();
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let n = 0;
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const fn = jest.fn(async () => {
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if (n < 5) {
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n += 1;
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throw "oops!";
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} else {
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// Fake timers don't play nicely with the `expect().rejects` API, so
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// ensure that the last attempt succeeds.
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return "success!";
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}
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});
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const promise = withRetry(
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fn,
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{
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attempts: 6,
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backoffMs: (attempt) => 1000 * 2 ** attempt,
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},
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)();
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expect(fn).toHaveBeenCalledTimes(1);
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await jest.advanceTimersByTimeAsync(100);
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expect(fn).toHaveBeenCalledTimes(1);
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await jest.advanceTimersByTimeAsync(1000);
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expect(fn).toHaveBeenCalledTimes(2);
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await jest.advanceTimersByTimeAsync(100);
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expect(fn).toHaveBeenCalledTimes(2);
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await jest.advanceTimersByTimeAsync(2000);
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expect(fn).toHaveBeenCalledTimes(3);
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await jest.advanceTimersByTimeAsync(100);
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expect(fn).toHaveBeenCalledTimes(3);
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await jest.advanceTimersByTimeAsync(4000);
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expect(fn).toHaveBeenCalledTimes(4);
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await jest.advanceTimersByTimeAsync(100);
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expect(fn).toHaveBeenCalledTimes(4);
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await jest.advanceTimersByTimeAsync(8000);
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expect(fn).toHaveBeenCalledTimes(5);
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await jest.advanceTimersByTimeAsync(100);
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expect(fn).toHaveBeenCalledTimes(5);
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await jest.advanceTimersByTimeAsync(16000);
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expect(fn).toHaveBeenCalledTimes(6);
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await expect(promise).resolves.toEqual("success!")
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// Fake timers don't play nicely with the `expect().rejects` API, so disable
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// them again for other tests.
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jest.useRealTimers();
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});
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