From 5b8382b9a18012729dbe657317c59099c14e453c Mon Sep 17 00:00:00 2001
From: Simen Bekkhus <sbekkhus91@gmail.com>
Date: Fri, 17 Apr 2020 13:14:51 +0200
Subject: [PATCH] fix: disallow hook defintions in tests

---
 CHANGELOG.md                                   |  1 +
 e2e/__tests__/nestedTestDefinitions.test.ts    | 14 ++++++++++++++
 .../__tests__/nestedHookInTest.js              | 18 ++++++++++++++++++
 packages/jest-circus/src/eventHandler.ts       |  9 ++++++++-
 4 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 e2e/nested-test-definitions/__tests__/nestedHookInTest.js

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6bef176537ff..904d4e425402 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
 - `[jest-circus, jest-console, jest-jasmine2, jest-reporters, jest-util, pretty-format]` Fix time durating formatting and consolidate time formatting code ([#9765](https://github.com/facebook/jest/pull/9765))
 - `[jest-circus]` [**BREAKING**] Fail tests if a test takes a done callback and have return values ([#9129](https://github.com/facebook/jest/pull/9129))
 - `[jest-circus]` [**BREAKING**] Throw a proper error if a test / hook is defined asynchronously ([#8096](https://github.com/facebook/jest/pull/8096))
+- `[jest-circus]` Throw more descriptive error if hook is defined inside test
 - `[jest-config, jest-resolve]` [**BREAKING**] Remove support for `browser` field ([#9943](https://github.com/facebook/jest/pull/9943))
 
 ### Chore & Maintenance
diff --git a/e2e/__tests__/nestedTestDefinitions.test.ts b/e2e/__tests__/nestedTestDefinitions.test.ts
index 0a26d4fc14c5..4eaa8f8ae0ac 100644
--- a/e2e/__tests__/nestedTestDefinitions.test.ts
+++ b/e2e/__tests__/nestedTestDefinitions.test.ts
@@ -55,3 +55,17 @@ test('print correct message when nesting describe inside it', () => {
     'Cannot nest a describe inside a test. Describe block "inner describe" cannot run because it is nested within "test".',
   );
 });
+
+test('print correct message when nesting a hook inside it', () => {
+  if (!isJestCircusRun()) {
+    return;
+  }
+
+  const result = runJest('nested-test-definitions', ['nestedHookInTest']);
+
+  expect(result.exitCode).toBe(1);
+
+  expect(result.stderr).toContain(
+    'Hooks cannot be defined inside tests. Hook of type "beforeEach" is nested within "test".',
+  );
+});
diff --git a/e2e/nested-test-definitions/__tests__/nestedHookInTest.js b/e2e/nested-test-definitions/__tests__/nestedHookInTest.js
new file mode 100644
index 000000000000..d7b403d9842c
--- /dev/null
+++ b/e2e/nested-test-definitions/__tests__/nestedHookInTest.js
@@ -0,0 +1,18 @@
+/**
+ * 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';
+
+const {getTruthy} = require('../index');
+
+test('test', () => {
+  expect(getTruthy()).toBeTruthy();
+
+  beforeEach(() => {
+    // nothing to see here
+  });
+});
diff --git a/packages/jest-circus/src/eventHandler.ts b/packages/jest-circus/src/eventHandler.ts
index 87a2061a649f..fbe74caea584 100644
--- a/packages/jest-circus/src/eventHandler.ts
+++ b/packages/jest-circus/src/eventHandler.ts
@@ -88,8 +88,15 @@ const eventHandler: Circus.EventHandler = (
       break;
     }
     case 'add_hook': {
-      const {currentDescribeBlock, hasStarted} = state;
+      const {currentDescribeBlock, currentlyRunningTest, hasStarted} = state;
       const {asyncError, fn, hookType: type, timeout} = event;
+
+      if (currentlyRunningTest) {
+        throw new Error(
+          `Hooks cannot be defined inside tests. Hook of type "${type}" is nested within "${currentlyRunningTest.name}".`,
+        );
+      }
+
       const parent = currentDescribeBlock;
 
       if (hasStarted) {