From 8084a326f0ecaa2d1848a42ae1306767b39533ab Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Fri, 5 Aug 2016 18:39:50 +0100
Subject: [PATCH] Tweak Jest default settings (#378)

Disable timer mocking and enable verbose output.
---
 config/jest/environment.js        | 7 +++++++
 scripts/eject.js                  | 1 +
 scripts/utils/createJestConfig.js | 4 +++-
 3 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 config/jest/environment.js

diff --git a/config/jest/environment.js b/config/jest/environment.js
new file mode 100644
index 00000000000..e7c1df906c6
--- /dev/null
+++ b/config/jest/environment.js
@@ -0,0 +1,7 @@
+// Currently, Jest mocks setTimeout() and similar functions by default:
+// https://facebook.github.io/jest/docs/timer-mocks.html
+// We think this is confusing, so we disable this feature.
+// If you see value in it, run `jest.useFakeTimers()` in individual tests.
+beforeEach(() => {
+  jest.useRealTimers();
+});
diff --git a/scripts/eject.js b/scripts/eject.js
index 82202d6eed9..55661d19285 100644
--- a/scripts/eject.js
+++ b/scripts/eject.js
@@ -41,6 +41,7 @@ prompt(
     path.join('config', 'webpack.config.prod.js'),
     path.join('config', 'jest', 'CSSStub.js'),
     path.join('config', 'jest', 'FileStub.js'),
+    path.join('config', 'jest', 'environment.js'),
     path.join('config', 'jest', 'transform.js'),
     path.join('scripts', 'build.js'),
     path.join('scripts', 'start.js'),
diff --git a/scripts/utils/createJestConfig.js b/scripts/utils/createJestConfig.js
index 282705f0dd3..d4ee867f473 100644
--- a/scripts/utils/createJestConfig.js
+++ b/scripts/utils/createJestConfig.js
@@ -19,7 +19,9 @@ module.exports = (resolve, rootDir) => {
     setupFiles: [
       resolve('config/polyfills.js')
     ],
-    testEnvironment: 'node'
+    setupTestFrameworkScriptFile: resolve('config/jest/environment.js'),
+    testEnvironment: 'node',
+    verbose: true
   };
   if (rootDir) {
     config.rootDir = rootDir;