Concurrency limit

CHANGELOG.md

@@ -5,6 +5,7 @@
 - `[jest-resolve]`: Pass default resolver into custom resolvers ([#7714](https://github.com/facebook/jest/pull/7714))
 - `[jest-cli]`: `global{Setup,Teardown}` use default export with es modules ([#7750](https://github.com/facebook/jest/pull/7750))
 - `[jest-runtime]` Better error messages when the jest environment is used after teardown by async code ([#7756](https://github.com/facebook/jest/pull/7756))
+- `[jest-jasmine2]` Will now only execute at most 5 concurrent tests *within the same testsuite* when using `test.concurrent`
 
 ### Fixes
 

TestUtils.js

@@ -36,6 +36,7 @@ const DEFAULT_GLOBAL_CONFIG: GlobalConfig = {
   lastCommit: false,
   listTests: false,
   logHeapUsage: false,
+  maxConcurrency: 5,
   maxWorkers: 2,
   noSCM: null,
   noStackTrace: false,

e2e/__tests__/jasmineAsync.test.js

@@ -125,6 +125,15 @@ describe('async jasmine', () => {
     expect(json.testResults[0].message).toMatch(/concurrent test fails/);
   });
 
+  it("doesn't execute more than 5 tests simultaneously", () => {
+    const result = runWithJson('jasmine-async', ['concurrent-many.test.js']);
+    const json = result.json;
+    expect(json.numTotalTests).toBe(10);
+    expect(json.numPassedTests).toBe(10);
+    expect(json.numFailedTests).toBe(0);
+    expect(json.numPendingTests).toBe(0);
+  });
+
   it('async test fails', () => {
     const result = runWithJson('jasmine-async', ['asyncTestFails.test.js']);
 

e2e/jasmine-async/__tests__/concurrent-many.test.js

@@ -0,0 +1,27 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+'use strict';
+
+const sleep = duration => new Promise(resolve => setTimeout(resolve, duration));
+let current = 0;
+
+for (let t = 0; t < 10; ++t) {
+  it.concurrent(`#${t}`, async () => {
+    current += 1;
+
+    try {
+      if (current > 5) {
+        throw new Error(`Too many processes ran simultaneously`);
+      } else {
+        await sleep(20);
+      }
+    } finally {
+      current -= 1;
+    }
+  });
+}

packages/jest-circus/package.json

@@ -20,7 +20,8 @@
     "jest-snapshot": "^24.0.0",
     "jest-util": "^24.0.0",
     "pretty-format": "^24.0.0",
-    "stack-utils": "^1.0.1"
+    "stack-utils": "^1.0.1",
+    "throat": "^4.0.0"
   },
   "devDependencies": {
     "execa": "^1.0.0",

packages/jest-circus/src/legacy-code-todo-rewrite/jestAdapterInit.js

@@ -18,6 +18,7 @@ import {
   addSerializer,
   buildSnapshotResolver,
 } from 'jest-snapshot';
+import throat from 'throat';
 import {addEventHandler, dispatch, ROOT_DESCRIBE_BLOCK_NAME} from '../state';
 import {getTestID} from '../utils';
 import run from '../run';
@@ -41,6 +42,8 @@ export const initialize = ({
   testPath: Path,
   parentProcess: Process,
 }) => {
+  const mutex = throat(globalConfig.maxConcurrency);
+
   Object.assign(global, globals);
 
   global.xit = global.it.skip;
@@ -60,7 +63,7 @@ export const initialize = ({
     // Unfortunately at this stage there's no way to know if there are any `.only` tests in the suite
     // that will result in this test to be skipped, so we'll be executing the promise function anyway,
     // even if it ends up being skipped.
-    const promise = testFn();
+    const promise = mutex(() => testFn());
     global.test(testName, () => promise, timeout);
   };
 
@@ -69,7 +72,7 @@ export const initialize = ({
     testFn: () => Promise<any>,
     timeout?: number,
   ) => {
-    const promise = testFn();
+    const promise = mutex(() => testFn());
     global.test.only(testName, () => promise, timeout);
   };
 

packages/jest-cli/src/cli/args.js

@@ -335,6 +335,13 @@ export const options = {
       'when transformers supply source maps.\n\nDEPRECATED',
     type: 'boolean',
   },
+  maxConcurrency: {
+    default: 5,
+    description:
+      'Specifies the maximum number of tests that are allowed to run' +
+      'concurrently. This only affects tests using `test.concurrent`.',
+    type: 'number',
+  },
   maxWorkers: {
     alias: 'w',
     description:

packages/jest-config/src/Defaults.js

@@ -42,6 +42,7 @@ export default ({
     computeSha1: false,
     providesModuleNodeModules: [],
   },
+  maxConcurrency: 5,
   moduleDirectories: ['node_modules'],
   moduleFileExtensions: ['js', 'json', 'jsx', 'ts', 'tsx', 'node'],
   moduleNameMapper: {},

packages/jest-config/src/ValidConfig.js

@@ -62,6 +62,7 @@ export default ({
   json: false,
   lastCommit: false,
   logHeapUsage: true,
+  maxConcurrency: 5,
   moduleDirectories: ['node_modules'],
   moduleFileExtensions: ['js', 'json', 'jsx', 'ts', 'tsx', 'node'],
   moduleLoader: '<rootDir>',

packages/jest-config/src/index.js

@@ -131,6 +131,7 @@ const groupOptions = (
     lastCommit: options.lastCommit,
     listTests: options.listTests,
     logHeapUsage: options.logHeapUsage,
+    maxConcurrency: options.maxConcurrency,
     maxWorkers: options.maxWorkers,
     noSCM: undefined,
     noStackTrace: options.noStackTrace,

packages/jest-config/src/normalize.js

@@ -713,6 +713,7 @@ export default function normalize(
       case 'lastCommit':
       case 'listTests':
       case 'logHeapUsage':
+      case 'maxConcurrency':
       case 'mapCoverage':
       case 'name':
       case 'noStackTrace':
@@ -803,6 +804,7 @@ export default function normalize(
       ? 'all'
       : 'new';
 
+  newOptions.maxConcurrency = parseInt(newOptions.maxConcurrency, 10);
   newOptions.maxWorkers = getMaxWorkers(argv);
 
   if (newOptions.testRegex.length && options.testMatch) {

packages/jest-jasmine2/package.json

@@ -19,7 +19,8 @@
     "jest-message-util": "^24.0.0",
     "jest-snapshot": "^24.0.0",
     "jest-util": "^24.0.0",
-    "pretty-format": "^24.0.0"
+    "pretty-format": "^24.0.0",
+    "throat": "^4.0.0"
   },
   "devDependencies": {
     "jest-diff": "^24.0.0",

packages/jest-jasmine2/src/index.js

@@ -75,7 +75,7 @@ async function jasmine2(
     };
   }
 
-  jasmineAsyncInstall(environment.global);
+  jasmineAsyncInstall(globalConfig, environment.global);
 
   installEach(environment);
 

packages/jest-jasmine2/src/jasmineAsyncInstall.js

@@ -13,9 +13,11 @@
  */
 
 import type {Global} from 'types/Global';
+import type {GlobalConfig} from 'types/Config';
 
-import isGeneratorFn from 'is-generator-fn';
 import co from 'co';
+import isGeneratorFn from 'is-generator-fn';
+import throat from 'throat';
 import isError from './isError';
 
 function isPromise(obj) {
@@ -125,21 +127,23 @@ function promisifyIt(originalFn, env, jasmine) {
   };
 }
 
-function makeConcurrent(originalFn: Function, env) {
+function makeConcurrent(originalFn: Function, env, mutex) {
   return function(specName, fn, timeout) {
     if (env != null && !env.specFilter({getFullName: () => specName || ''})) {
       return originalFn.call(env, specName, () => Promise.resolve(), timeout);
     }
 
     let promise;
-
     try {
-      promise = fn();
-      if (!isPromise(promise)) {
+      promise = mutex(() => {
+        const promise = fn();
+        if (isPromise(promise)) {
+          return promise;
+        }
         throw new Error(
           `Jest: concurrent test "${specName}" must return a Promise.`,
         );
-      }
+      });
     } catch (error) {
       return originalFn.call(env, specName, () => Promise.reject(error));
     }
@@ -148,16 +152,20 @@ function makeConcurrent(originalFn: Function, env) {
   };
 }
 
-export default function jasmineAsyncInstall(global: Global) {
+export default function jasmineAsyncInstall(
+  globalConfig: GlobalConfig,
+  global: Global,
+) {
   const jasmine = global.jasmine;
+  const mutex = throat(globalConfig.maxConcurrency);
 
   const env = jasmine.getEnv();
   env.it = promisifyIt(env.it, env, jasmine);
   env.fit = promisifyIt(env.fit, env, jasmine);
-  global.it.concurrent = makeConcurrent(env.it, env);
-  global.it.concurrent.only = makeConcurrent(env.fit, env);
-  global.it.concurrent.skip = makeConcurrent(env.xit, env);
-  global.fit.concurrent = makeConcurrent(env.fit);
+  global.it.concurrent = makeConcurrent(env.it, env, mutex);
+  global.it.concurrent.only = makeConcurrent(env.fit, env, mutex);
+  global.it.concurrent.skip = makeConcurrent(env.xit, env, mutex);
+  global.fit.concurrent = makeConcurrent(env.fit, env, mutex);
   env.afterAll = promisifyLifeCycleFunction(env.afterAll, env);
   env.afterEach = promisifyLifeCycleFunction(env.afterEach, env);
   env.beforeAll = promisifyLifeCycleFunction(env.beforeAll, env);

types/Config.js

@@ -46,6 +46,7 @@ export type DefaultOptions = {|
   globalSetup: ?string,
   globalTeardown: ?string,
   haste: HasteConfig,
+  maxConcurrency: number,
   moduleDirectories: Array<string>,
   moduleFileExtensions: Array<string>,
   moduleNameMapper: {[key: string]: string},
@@ -124,7 +125,8 @@ export type InitialOptions = {
   lastCommit?: boolean,
   listTests?: boolean,
   mapCoverage?: boolean,
-  moduleDirectories?: Array<string>,
+  maxConcurrency?: number,
+  moduleDirectories?: Array<string?>,
   moduleFileExtensions?: Array<string>,
   moduleLoader?: Path,
   moduleNameMapper?: {[key: string]: string},
@@ -213,6 +215,7 @@ export type GlobalConfig = {|
   lastCommit: boolean,
   logHeapUsage: boolean,
   listTests: boolean,
+  maxConcurrency: number,
   maxWorkers: number,
   noStackTrace: boolean,
   nonFlagArgs: Array<string>,

yarn.lock

@@ -3553,11 +3553,6 @@ core-js@^2.2.0, core-js@^2.2.2, core-js@^2.4.0, core-js@^2.4.1, core-js@^2.5.7:
   resolved "https://registry.yarnpkg.com/core-js/-/core-js-2.6.3.tgz#4b70938bdffdaf64931e66e2db158f0892289c49"
   integrity sha512-l00tmFFZOBHtYhN4Cz7k32VM7vTn3rE2ANjQDxdEN6zmXZ/xq1jQuutnmHvMG1ZJ7xd72+TA5YpUK8wz3rWsfQ==
 
-core-js@^2.5.0:
-  version "2.6.3"
-  resolved "https://registry.yarnpkg.com/core-js/-/core-js-2.6.3.tgz#4b70938bdffdaf64931e66e2db158f0892289c49"
-  integrity sha512-l00tmFFZOBHtYhN4Cz7k32VM7vTn3rE2ANjQDxdEN6zmXZ/xq1jQuutnmHvMG1ZJ7xd72+TA5YpUK8wz3rWsfQ==
-
 [email protected], core-util-is@~1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/core-util-is/-/core-util-is-1.0.2.tgz#b5fd54220aa2bc5ab57aab7140c940754503c1a7"