fix: spyOn should not rely on hasOwnProperty from the spied object

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixes
 
 - `[jest-environment-node]` Add `Event` and `EventTarget` to node global environment. ([#11705](https://github.com/facebook/jest/issues/11705))
+- `[jest-mock]` Fix `spyOn` to use `Object.prototype.hasOwnProperty` [#11721](https://github.com/facebook/jest/pull/11721)
 
 ### Chore & Maintenance
 

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

@@ -1216,6 +1216,18 @@ describe('moduleMocker', () => {
  expect(originalCallArguments[1]).toBe(secondArg);
  expect(spy).not.toHaveBeenCalled();
  });
+
+ it('should work with object of null prototype', () => {
+ const Foo = Object.assign(Object.create(null), {
+ foo() {},
+ });
+
+ const spy = moduleMocker.spyOn(Foo, 'foo');
+
+ Foo.foo();
+
+ expect(spy).toHaveBeenCalled();
+ });
  });
 
  describe('spyOnProperty', () => {

packages/jest-mock/src/index.ts

@@ -976,7 +976,10 @@ export class ModuleMocker {
  );
  }
 
- const isMethodOwner = object.hasOwnProperty(methodName);
+ const isMethodOwner = Object.prototype.hasOwnProperty.call(
+ object,
+ methodName,
+ );
 
  let descriptor = Object.getOwnPropertyDescriptor(object, methodName);
  let proto = Object.getPrototypeOf(object);