fix: Fix jest-mock fn and spyOn. (#11480)

Author: cpojer

CHANGELOG.md

@@ -8,6 +8,12 @@
 
 ### Performance
 
+## 27.0.3
+
+### Fixes
+
+- `[jest-mock]` Fixed `fn` and `spyOn` exports ([#11480](https://github.com/facebook/jest/pull/11480))
+
 ## 27.0.2
 
 ### Features

packages/jest-mock/src/__tests__/index.test.ts

@@ -9,7 +9,7 @@
 /* eslint-disable local/ban-types-eventually, local/prefer-rest-params-eventually */
 
 import vm, {Context} from 'vm';
-import {ModuleMocker} from '../';
+import {ModuleMocker, fn, spyOn} from '../';
 
 describe('moduleMocker', () => {
   let moduleMocker: ModuleMocker;
@@ -1439,3 +1439,10 @@ describe('moduleMocker', () => {
     });
   });
 });
+
+test('`fn` and `spyOn` do not throw', () => {
+  expect(() => {
+    fn();
+    spyOn({apple: () => {}}, 'apple');
+  }).not.toThrow();
+});

packages/jest-mock/src/index.ts

@@ -1112,5 +1112,5 @@ export class ModuleMocker {
 
 const JestMock = new ModuleMocker(global);
 
-export const fn = JestMock.fn;
-export const spyOn = JestMock.spyOn;
+export const fn = JestMock.fn.bind(JestMock);
+export const spyOn = JestMock.spyOn.bind(JestMock);