From 1ad9864ad72181932ee4433a2dce8d8b333661b8 Mon Sep 17 00:00:00 2001
From: Lucas Fernandes da Costa <lucas@lucasfcosta.com>
Date: Mon, 1 Jul 2019 21:08:00 +0100
Subject: [PATCH] fix(jest-mock): fix mock restoration reassigning to
previously unexisting prop (#8625)
---
CHANGELOG.md | 1 +
.../jest-mock/src/__tests__/index.test.ts | 26 +++++++++++++++++++
packages/jest-mock/src/index.ts | 8 +++++-
3 files changed, 34 insertions(+), 1 deletion(-)
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5c57e8fc17c7..2bb3607b3b6d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,7 @@
- `[jest-haste-map]` Don't throw on missing mapper in Node crawler ([#8558](https://github.com/facebook/jest/pull/8558))
- `[jest-core]` Fix incorrect `passWithNoTests` warning ([#8595](https://github.com/facebook/jest/pull/8595))
- `[jest-snapshots]` Fix test retries that contain snapshots ([#8629](https://github.com/facebook/jest/pull/8629))
+- `[jest-mock]` Fix incorrect assignments when restoring mocks in instances where they originally didn't exist ([#8631](https://github.com/facebook/jest/pull/8631))
### Chore & Maintenance
diff --git a/packages/jest-mock/src/__tests__/index.test.ts b/packages/jest-mock/src/__tests__/index.test.ts
index 64c47464be83..f665def33ea6 100644
--- a/packages/jest-mock/src/__tests__/index.test.ts
+++ b/packages/jest-mock/src/__tests__/index.test.ts
@@ -542,6 +542,32 @@ describe('moduleMocker', () => {
});
});
+ it('mocks the method in the passed object itself', () => {
+ const parent = {func: () => 'abcd'};
+ const child = Object.create(parent);
+
+ moduleMocker.spyOn(child, 'func').mockReturnValue('efgh');
+
+ expect(child.hasOwnProperty('func')).toBe(true);
+ expect(child.func()).toEqual('efgh');
+ expect(parent.func()).toEqual('abcd');
+ });
+
+ it('should delete previously inexistent methods when restoring', () => {
+ const parent = {func: () => 'abcd'};
+ const child = Object.create(parent);
+
+ moduleMocker.spyOn(child, 'func').mockReturnValue('efgh');
+
+ moduleMocker.restoreAllMocks();
+ expect(child.func()).toEqual('abcd');
+
+ moduleMocker.spyOn(parent, 'func').mockReturnValue('jklm');
+
+ expect(child.hasOwnProperty('func')).toBe(false);
+ expect(child.func()).toEqual('jklm');
+ });
+
it('supports mock value returning undefined', () => {
const obj = {
func: () => 'some text',
diff --git a/packages/jest-mock/src/index.ts b/packages/jest-mock/src/index.ts
index 7647b81c379a..be19de0df52f 100644
--- a/packages/jest-mock/src/index.ts
+++ b/packages/jest-mock/src/index.ts
@@ -1009,9 +1009,15 @@ class ModuleMockerClass {
);
}
+ const isMethodOwner = object.hasOwnProperty(methodName);
+
// @ts-ignore overriding original method with a Mock
object[methodName] = this._makeComponent({type: 'function'}, () => {
- object[methodName] = original;
+ if (isMethodOwner) {
+ object[methodName] = original;
+ } else {
+ delete object[methodName];
+ }
});
// @ts-ignore original method is now a Mock