Fix missing console log output in verbose mode

CHANGELOG.md

@@ -35,6 +35,7 @@
 
 ### Fixes
 
+- `[jest-runner/jest-worker]` Fix missing console output in verbose mode ([#6871](https://github.com/facebook/jest/pull/6871))
 - `[expect]` Standardize file naming in `expect` ([#7306](https://github.com/facebook/jest/pull/7306))
 - `[jest-each]` Add empty array validation check ([#7249](https://github.com/facebook/jest/pull/7249))
 - `[jest-cli]` Interrupt tests if interactive watch plugin key is pressed ([#7222](https://github.com/facebook/jest/pull/7222))

packages/jest-runner/src/index.js

@@ -97,11 +97,14 @@ class TestRunner {
     // $FlowFixMe: class object is augmented with worker when instantiating.
     const worker: WorkerInterface = new Worker(TEST_WORKER_PATH, {
       exposedMethods: ['worker'],
-      forkOptions: {stdio: 'inherit'},
+      forkOptions: {stdio: 'pipe'},
       maxRetries: 3,
       numWorkers: this._globalConfig.maxWorkers,
     });
 
+    if (worker.getStdout()) worker.getStdout().pipe(process.stdout);
+    if (worker.getStderr()) worker.getStderr().pipe(process.stderr);
+
     const mutex = throat(this._globalConfig.maxWorkers);
 
     // Send test suites to workers continuously instead of all at once to track

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';
 
+import supportsColor from 'supports-color';
+
 /**
  * This class wraps the child process and provides a nice interface to
  * communicate with. It takes care of:
@@ -88,15 +90,21 @@ export default class {
   }
 
   _initialize() {
+    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, {
-            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,

packages/jest-worker/src/__tests__/Worker.test.js

@@ -10,6 +10,7 @@
 /* eslint-disable no-new */
 
 import EventEmitter from 'events';
+import supportsColor from 'supports-color';
 
 import {
   CHILD_MESSAGE_CALL,
@@ -64,7 +65,9 @@ it('passes fork options down to child_process.fork, adding the defaults', () =>
   expect(childProcess.fork.mock.calls[0][0]).toBe(child);
   expect(childProcess.fork.mock.calls[0][1]).toEqual({
     cwd: '/tmp', // Overridden default option.
-    env: process.env, // Default option.
+    env: Object.assign({}, process.env, {
+      FORCE_COLOR: supportsColor.stdout ? '1' : undefined,
+    }), // Default option.
     execArgv: ['-p'], // Filtered option.
     execPath: 'hello', // Added option.
     silent: true, // Default option.

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==