Fix a flaky test that behaves differently in various situations.

Author: cpojer

e2e/__tests__/circusConcurrent.test.ts

@@ -4,12 +4,13 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
-import exp = require('constants');
 import {skipSuiteOnJasmine} from '@jest/test-utils';
 import runJest, {json as runWithJson} from '../runJest';
 
 skipSuiteOnJasmine();
 
+jest.retryTimes(3);
+
 describe('all passing', () => {
   it('runs the correct number of tests', () => {
     const {json, exitCode} = runWithJson('circus-concurrent', [

packages/jest-worker/src/workers/__tests__/ChildProcessWorker.test.ts

@@ -30,6 +30,7 @@ let Worker: typeof import('../ChildProcessWorker').default;
 let childProcess: typeof import('child_process');
 let forkInterface: ReturnType<typeof childProcess.fork>;
 let originalExecArgv: typeof process.execArgv;
+let originalForceColor: string | undefined;
 
 const totalmem = jest.spyOn(require('os') as typeof import('os'), 'totalmem');
 
@@ -42,6 +43,9 @@ class MockedForkInterface extends EventEmitter {
 }
 
 beforeEach(() => {
+  originalForceColor = process.env.FORCE_COLOR;
+  delete process.env.FORCE_COLOR;
+
   originalExecArgv = process.execArgv;
 
   childProcess = require('child_process') as typeof import('child_process');
@@ -63,6 +67,7 @@ beforeEach(() => {
 afterEach(() => {
   jest.resetModules();
   process.execArgv = originalExecArgv;
+  process.env.FORCE_COLOR = originalForceColor;
 });
 
 it('passes fork options down to child_process.fork, adding the defaults', () => {
@@ -84,7 +89,7 @@ it('passes fork options down to child_process.fork, adding the defaults', () =>
   expect(jest.mocked(childProcess.fork).mock.calls[0][0]).toBe(child);
   expect(jest.mocked(childProcess.fork).mock.calls[0][2]).toEqual({
     cwd: '/tmp', // Overridden default option.
-    env: {...process.env, FORCE_COLOR: supportsColor.stdout ? '1' : undefined}, // Default option.
+    env: process.env, // Default option.
     execArgv: ['-p'], // Filtered option.
     execPath: 'hello', // Added option.
     serialization: 'advanced', // Default option.