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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.import { _exponentialBackoffWithJitter, retry, RetryError } from "./retry.ts";import { assertEquals, assertRejects } from "../assert/mod.ts";import { FakeTime } from "../testing/time.ts";
function generateErroringFunction(errorsBeforeSucceeds: number) {  let errorCount = 0;
  return () => {    if (errorCount >= errorsBeforeSucceeds) {      return errorCount;    }    errorCount++;    throw `Only errored ${errorCount} times`;  };}
Deno.test("[async] retry", async function () {  const threeErrors = generateErroringFunction(3);  const result = await retry(threeErrors, {    minTimeout: 100,  });  assertEquals(result, 3);});
Deno.test("[async] retry fails after max errors is passed", async function () {  const fiveErrors = generateErroringFunction(5);  await assertRejects(() =>    retry(fiveErrors, {      minTimeout: 100,    })  );});
Deno.test("[async] retry waits four times by default", async function () {  let callCount = 0;  const onlyErrors = function () {    callCount++;    throw new Error("Failure");  };  const time = new FakeTime();  const callCounts: Array<number> = [];  try {    const promise = retry(onlyErrors);    queueMicrotask(() => callCounts.push(callCount));    await time.next();    queueMicrotask(() => callCounts.push(callCount));    await time.next();    queueMicrotask(() => callCounts.push(callCount));    await time.next();    queueMicrotask(() => callCounts.push(callCount));    await time.next();    queueMicrotask(() => callCounts.push(callCount));    await assertRejects(() => promise, RetryError);    assertEquals(callCounts, [1, 2, 3, 4, 5]);  } finally {    time.restore();  }});
Deno.test(  "[async] retry throws if minTimeout is less than maxTimeout",  async function () {    await assertRejects(() =>      retry(() => {}, {        minTimeout: 1000,        maxTimeout: 100,      })    );  },);
Deno.test(  "[async] retry throws if maxTimeout is less than 0",  async function () {    await assertRejects(() =>      retry(() => {}, {        maxTimeout: -1,      })    );  },);
Deno.test(  "[async] retry throws if jitter is bigger than 1",  async function () {    await assertRejects(() =>      retry(() => {}, {        jitter: 2,      })    );  },);
// test util to ensure deterministic results during testing of backoff function by polyfilling Math.randomfunction prngMulberry32(seed: number) {  return function () {    let t = (seed += 0x6d2b79f5);    t = Math.imul(t ^ (t >>> 15), t | 1);    t ^= t + Math.imul(t ^ (t >>> 7), t | 61);    return ((t ^ (t >>> 14)) >>> 0);  };}
// random seed generated with crypto.getRandomValues(new Uint32Array(1))[0]const INITIAL_SEED = 3460544849;
const expectedTimings: readonly (readonly number[] & { length: 10 })[] & {  length: 10;} = [  [31, 117, 344, 9, 1469, 1060, 920, 5094, 19564, 33292],  [46, 184, 377, 419, 1455, 483, 3205, 8426, 22451, 29810],  [68, 17, 66, 645, 1209, 246, 3510, 4598, 398, 12813],  [46, 111, 374, 626, 859, 1955, 5379, 609, 5766, 33641],  [26, 129, 287, 757, 1104, 4, 2557, 4940, 16657, 6888],  [80, 71, 348, 245, 743, 128, 2445, 5722, 19960, 49861],  [25, 46, 341, 498, 602, 2349, 1366, 4399, 1680, 9275],  [14, 174, 189, 309, 1461, 937, 1898, 2087, 9624, 18872],  [65, 190, 382, 351, 826, 2502, 5657, 3967, 1063, 43754],  [89, 78, 222, 668, 1027, 1397, 1293, 8295, 14077, 33602],] as const;
Deno.test("[async] retry - backoff function timings", async (t) => {  const originalMathRandom = Math.random;
  await t.step("wait fixed times without jitter", async function () {    const time = new FakeTime();    let resolved = false;    const checkResolved = async () => {      try {        await retry(() => {          throw new Error("Failure");        }, { jitter: 0 });      } catch {        resolved = true;      }    };    try {      const promise = checkResolved();      const startTime = time.now;
      await time.nextAsync();      assertEquals(time.now - startTime, 1000);
      await time.nextAsync();      assertEquals(time.now - startTime, 3000);
      await time.nextAsync();      assertEquals(time.now - startTime, 7000);
      await time.nextAsync();      assertEquals(time.now - startTime, 15000);      assertEquals(resolved, false);
      await time.runMicrotasks();      assertEquals(time.now - startTime, 15000);      assertEquals(resolved, true);
      await time.runAllAsync();      assertEquals(time.now - startTime, 15000);      await promise;    } finally {      time.restore();    }  });
  await t.step("_exponentialBackoffWithJitter", () => {    let nextSeed = INITIAL_SEED;
    for (const row of expectedTimings) {      const randUint32 = prngMulberry32(nextSeed);      nextSeed = prngMulberry32(nextSeed)();      Math.random = () => randUint32() / 0x100000000;
      const results: number[] = [];      const base = 100;      const cap = Infinity;
      for (let i = 0; i < 10; ++i) {        const result = _exponentialBackoffWithJitter(cap, base, i, 2, 1);        results.push(Math.round(result));      }
      assertEquals(results as typeof row, row);    }  });
  Math.random = originalMathRandom;});