deno/cli/tests/workers_test.ts

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.

// Requires to be run with `--allow-net` flag

// FIXME(bartlomieju): this file is an integration test only because
// workers are leaking ops at the moment - `worker.terminate()` is not
// yet implemented. Once it gets implemented this file should be
// again moved to `cli/js/` as an unit test file.

import { assert, assertEquals } from "../../std/testing/asserts.ts";

export interface ResolvableMethods<T> {
  resolve: (value?: T | PromiseLike<T>) => void;
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  reject: (reason?: any) => void;
}

export type Resolvable<T> = Promise<T> & ResolvableMethods<T>;

export function createResolvable<T>(): Resolvable<T> {
  let methods: ResolvableMethods<T>;
  const promise = new Promise<T>((resolve, reject): void => {
    methods = { resolve, reject };
  });
  // TypeScript doesn't know that the Promise callback occurs synchronously
  // therefore use of not null assertion (`!`)
  return Object.assign(promise, methods!) as Resolvable<T>;
}

Deno.test(async function workersBasic(): Promise<void> {
  const promise = createResolvable();
  const jsWorker = new Worker("../tests/subdir/test_worker.js", {
    type: "module",
    name: "jsWorker"
  });
  const tsWorker = new Worker("../tests/subdir/test_worker.ts", {
    type: "module",
    name: "tsWorker"
  });

  tsWorker.onmessage = (e): void => {
    assertEquals(e.data, "Hello World");
    promise.resolve();
  };

  jsWorker.onmessage = (e): void => {
    assertEquals(e.data, "Hello World");
    tsWorker.postMessage("Hello World");
  };

  jsWorker.onerror = (e: Event): void => {
    e.preventDefault();
    jsWorker.postMessage("Hello World");
  };

  jsWorker.postMessage("Hello World");
  await promise;
});

Deno.test(async function nestedWorker(): Promise<void> {
  const promise = createResolvable();

  const nestedWorker = new Worker("../tests/subdir/nested_worker.js", {
    type: "module",
    name: "nested"
  });

  nestedWorker.onmessage = (e): void => {
    assert(e.data.type !== "error");
    promise.resolve();
  };

  nestedWorker.postMessage("Hello World");
  await promise;
});

Deno.test(async function workerThrowsWhenExecuting(): Promise<void> {
  const promise = createResolvable();
  const throwingWorker = new Worker("../tests/subdir/throwing_worker.js", {
    type: "module"
  });

  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  throwingWorker.onerror = (e: any): void => {
    e.preventDefault();
    assert(/Uncaught Error: Thrown error/.test(e.message));
    promise.resolve();
  };

  await promise;
});

Deno.test(async function workerCanUseFetch(): Promise<void> {
  const promise = createResolvable();

  const fetchingWorker = new Worker("../tests/subdir/fetching_worker.js", {
    type: "module"
  });

  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  fetchingWorker.onerror = (e: any): void => {
    e.preventDefault();
    promise.reject(e.message);
  };

  // Defer promise.resolve() to allow worker to shut down
  fetchingWorker.onmessage = (e): void => {
    assert(e.data === "Done!");
    promise.resolve();
  };

  await promise;
});

await Deno.runTests();