strip ansi codes from buggy version of supportsColor

e2e/__tests__/coverage_report.test.js

@@ -187,11 +187,11 @@ test('collects coverage from duplicate files avoiding shared cache', () => {
 });
 
 test('generates coverage when using the testRegex config param ', () => {
-  const {stdout, status} = runJest(DIR, [
-    '--no-cache',
-    '--testRegex=__tests__',
-    '--coverage',
-  ]);
+  const {stdout, status} = runJest(
+    DIR,
+    ['--no-cache', '--testRegex=__tests__', '--coverage'],
+    //{stripAnsi: true},
+  );
   expect(stdout).toMatchSnapshot();
   expect(status).toBe(0);
 });

e2e/__tests__/typescript_coverage.test.js

@@ -7,9 +7,10 @@
  * @flow
  */
 
-import path from 'path';
-import {run} from '../Utils';
-import runJest from '../runJest';
+const path = require('path');
+const {run} = require('../Utils');
+const runJest = require('../runJest');
+const stripAnsi = require('strip-ansi');
 
 it('instruments and collects coverage for typescript files', () => {
   const dir = path.resolve(__dirname, '../typescript-coverage');

packages/jest-worker/package.json

@@ -8,6 +8,7 @@
   "license": "MIT",
   "main": "build/index.js",
   "dependencies": {
+    "supports-color": "^5.5.0",
     "merge-stream": "^1.0.1"
   },
   "engines": {

packages/jest-worker/src/Worker.js

@@ -29,6 +29,8 @@ import type {
   WorkerOptions,
 } from './types';
 
+const supportsColor = require('supports-color');
+
 /**
  * This class wraps the child process and provides a nice interface to
  * communicate with. It takes care of:
@@ -88,23 +90,21 @@ export default class {
   }
 
   _initialize() {
-    const forceColor =
-      'FORCE_COLOR' in process.env
-        ? process.env['FORCE_COLOR']
-        : // $FlowFixMe: Does not know about isTTY
-          process.stdout.isTTY
-          ? '1'
-          : '0';
+    const forceColor = supportsColor.stdout ? {FORCE_COLOR: '1'} : {};
     const child = childProcess.fork(
       require.resolve('./child'),
       // $FlowFixMe: Flow does not work well with Object.assign.
       Object.assign(
         {
           cwd: process.cwd(),
-          env: Object.assign({}, process.env, {
-            FORCE_COLOR: forceColor,
-            JEST_WORKER_ID: this._options.workerId,
-          }),
+          env: Object.assign(
+            {},
+            process.env,
+            {
+              JEST_WORKER_ID: this._options.workerId,
+            },
+            forceColor,
+          ),
           // Suppress --debug / --inspect flags while preserving others (like --harmony).
           execArgv: process.execArgv.filter(v => !/^--(debug|inspect)/.test(v)),
           silent: true,

yarn.lock

@@ -12944,7 +12944,7 @@ supports-color@^3.1.2, supports-color@^3.2.3:
   dependencies:
     has-flag "^1.0.0"
 
-supports-color@^5.3.0, supports-color@^5.4.0:
+supports-color@^5.3.0, supports-color@^5.4.0, supports-color@^5.5.0:
   version "5.5.0"
   resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-5.5.0.tgz#e2e69a44ac8772f78a1ec0b35b689df6530efc8f"
   integrity sha512-QjVjwdXIt408MIiAqCX4oUKsgU2EqAGzs2Ppkm4aQYbjm+ZEWEcW4SfFNTr4uMNZma0ey4f5lgLrkB0aX0QMow==