fix: print log entries if logging happens after teardown

.flowconfig

@@ -1,6 +1,7 @@
 [ignore]
 .*/examples/.*
 .*/node_modules/metro-bundler/.*
+.*/node_modules/metro-config/.*
 .*/node_modules/metro/.*
 .*/node_modules/module-deps/.*
 

CHANGELOG.md

@@ -10,6 +10,7 @@
 - `[jest-config]` Extract setupFilesAfterEnv from preset ([#7724](https://github.com/facebook/jest/pull/7724))
 - `[jest-cli]` Do not execute any `globalSetup` or `globalTeardown` if there are no tests to execute ([#7745](https://github.com/facebook/jest/pull/7745))
 - `[jest-runtime]` Lock down version of `write-file-atomic` ([#7725](https://github.com/facebook/jest/pull/7725))
+- `[jest-cli]` Print log entries when logging happens after test environment is torn down ([#7731](https://github.com/facebook/jest/pull/7731))
 
 ### Chore & Maintenance
 

e2e/__tests__/__snapshots__/consoleAfterTeardown.test.js.snap

@@ -0,0 +1,20 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`console printing 1`] = `
+PASS __tests__/console.test.js
+
+
+  ●  Cannot log after tests are done. Did you forget to wait for something async in your test?
+    Attempted to log "hello!".
+
+      11 |   // eslint-disable-next-line prefer-arrow-callback
+      12 |   new Promise(resolve => setTimeout(resolve, 500)).then(function log() {
+    > 13 |     console.log('hello!');
+         |             ^
+      14 |   });
+      15 | });
+      16 | 
+
+      at BufferedConsole.log (../../packages/jest-util/build/BufferedConsole.js:169:10)
+      at log (__tests__/console.test.js:13:13)
+`;

e2e/__tests__/consoleAfterTeardown.test.js

@@ -0,0 +1,20 @@
+/**
+ * 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.
+ *
+ * @flow
+ */
+
+import {extractSummary} from '../Utils';
+import runJest from '../runJest';
+import {wrap} from 'jest-snapshot-serializer-raw';
+
+test('console printing', () => {
+  const {stderr, status} = runJest('console-after-teardown');
+  const {rest} = extractSummary(stderr);
+
+  expect(status).toBe(0);
+  expect(wrap(rest)).toMatchSnapshot();
+});

e2e/__tests__/forceExit.test.js

@@ -28,18 +28,25 @@ test('exits the process after test are done but before timers complete', () => {
     'package.json': JSON.stringify({jest: {testEnvironment: 'node'}}),
   });
 
+  let output;
   let stdout;
   let stderr;
   ({stdout, stderr} = runJest(DIR));
-  expect(stderr).toMatch(/PASS.*test\.test\.js/);
-  expect(stdout).toMatch(/TIMER_DONE/);
+
+  output = `${stdout}\n${stderr}`;
+
+  expect(output).toMatch(/PASS.*test\.test\.js/);
+  expect(output).toMatch(/TIMER_DONE/);
   writeFiles(DIR, {
     'package.json': JSON.stringify({
       jest: {forceExit: true, testEnvironment: 'node'},
     }),
   });
 
   ({stdout, stderr} = runJest(DIR));
-  expect(stderr).toMatch(/PASS.*test\.test\.js/);
-  expect(stdout).not.toMatch(/TIMER_DONE/);
+
+  output = `${stdout}\n${stderr}`;
+
+  expect(output).toMatch(/PASS.*test\.test\.js/);
+  expect(output).not.toMatch(/TIMER_DONE/);
 });

e2e/console-after-teardown/__tests__/console.test.js

@@ -0,0 +1,15 @@
+/**
+ * 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';
+
+test('throws error', () => {
+  // To have the function be named the same in jasmine and circus
+  // eslint-disable-next-line prefer-arrow-callback
+  new Promise(resolve => setTimeout(resolve, 500)).then(function log() {
+    console.log('hello!');
+  });
+});

e2e/console-after-teardown/package.json

@@ -0,0 +1,6 @@
+{
+  "jest": {
+    "testEnvironment": "node",
+    "verbose": false
+  }
+}

packages/jest-runner/package.json

@@ -9,6 +9,7 @@
   "license": "MIT",
   "main": "build/index.js",
   "dependencies": {
+    "chalk": "^2.4.2",
     "exit": "^0.1.2",
     "graceful-fs": "^4.1.15",
     "jest-config": "^24.0.0",

packages/jest-runner/src/runTest.js

@@ -28,12 +28,42 @@ import {getTestEnvironment} from 'jest-config';
 import * as docblock from 'jest-docblock';
 import {formatExecError} from 'jest-message-util';
 import sourcemapSupport from 'source-map-support';
+import chalk from 'chalk';
 
 type RunTestInternalResult = {
   leakDetector: ?LeakDetector,
   result: TestResult,
 };
 
+function freezeConsole(
+  testConsole: BufferedConsole | Console | NullConsole,
+  config: ProjectConfig,
+) {
+  // $FlowFixMe: overwrite it for pretty errors
+  testConsole._log = function fakeConsolePush(_type, message) {
+    const error = new ErrorWithStack(
+      `${chalk.red(
+        `${chalk.bold(
+          'Cannot log after tests are done.',
+        )} Did you forget to wait for something async in your test?`,
+      )}\nAttempted to log "${message}".`,
+      fakeConsolePush,
+    );
+
+    const formattedError = formatExecError(
+      error,
+      config,
+      {noStackTrace: false},
+      undefined,
+      true,
+    );
+
+    process.stderr.write('\n' + formattedError + '\n');
+    // TODO: set exit code in Jest 25
+    // process.exitCode = 1;
+  };
+}
+
 // Keeping the core of "runTest" as a separate function (as "runTestInternal")
 // is key to be able to detect memory leaks. Since all variables are local to
 // the function, when "runTestInternal" finishes its execution, they can all be
@@ -197,6 +227,8 @@ async function runTestInternal(
       throw err;
     }
 
+    freezeConsole(testConsole, config);
+
     const testCount =
       result.numPassingTests +
       result.numFailingTests +