123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081
// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.import { tee } from "./tee.ts";import { assertEquals } from "../assert/mod.ts";
/** An example async generator */const gen = async function* iter() {  yield 1;  yield 2;  yield 3;};
/** Testing utility for accumulating the values in async iterable. */async function accumulate<T>(src: AsyncIterable<T>): Promise<T[]> {  const res: T[] = [];  for await (const item of src) {    res.push(item);  }  return res;}
Deno.test("async/tee - 2 branches", async () => {  const iter = gen();  const [res0, res1] = tee(iter).map(accumulate);  assertEquals(    await Promise.all([res0, res1]),    [      [1, 2, 3],      [1, 2, 3],    ],  );});
Deno.test("async/tee - 3 branches - immediate consumption", async () => {  const iter = gen();  const [res0, res1, res2] = tee(iter, 3).map(accumulate);  assertEquals(    await Promise.all([res0, res1, res2]),    [      [1, 2, 3],      [1, 2, 3],      [1, 2, 3],    ],  );});
Deno.test("async/tee - 3 branches - delayed consumption", async () => {  const iter = gen();  const iters = tee(iter, 3);
  await new Promise<void>((resolve) => {    setTimeout(() => resolve(), 20);  });
  assertEquals(    await Promise.all(iters.map(accumulate)),    [      [1, 2, 3],      [1, 2, 3],      [1, 2, 3],    ],  );});
Deno.test("async/tee - concurrent .next calls", async () => {  const [left] = tee(gen());  const l = left[Symbol.asyncIterator]();  assertEquals(await Promise.all([l.next(), l.next(), l.next(), l.next()]), [{    value: 1,    done: false,  }, {    value: 2,    done: false,  }, {    value: 3,    done: false,  }, {    value: undefined,    done: true,  }]);});