fix: spyOn should not rely on hasOwnProperty from the spied object (jestjs#11721)

Author: cexbrayat

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - `[jest-types]` Compat with `@types/node` v16 ([#11645](https://github.com/facebook/jest/pull/11645))
 - `[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

@@ -974,7 +974,10 @@ 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);