Unit test, mocking components

ShareCom.js

import { InstallCom } from 'installComponent' //installed by npm
import UserCom from './userComponent'

export class ShareCom extends Component {
    render() {
        return (
          <div>
              <InstallCom para1='title1'/>
              <UserCom para2='title2' />
          </div>
        )
      }
}

test.js

import {ShareCom} from '../somewhere/ShareCom'

jest.mock('../somewhere/UserCom', () => ()=> <div id="mockUserCom">mockUserCom</div>)
jest.mock('installComponent', () => ({
    InstallCom: 'mockInstallCom'
}))

describe('ShareCom', () => {
    it('should return correct component', () => {
      const wrapper = mount(
        <ShareCom
          something={something}
        />
      )
  
      expect(wrapper.find('mockInstallCom').length).toEqual(1)
      expect(wrapper.find('#mockUserCom').length).toEqual(1)
    })
})

i whant understand when i write this mock :const mockValidateObject = jest.fn(({ entityName, object, configData }) => {
if (entityName instanceof String) {
return true;
} else {
return false;
}
})
jest.mock('../../../modules/validation', () => {
return {
validateObject: mockValidateObject,
}
})and when i write this mock:jest.mock('../../../modules/validation', () => ({
validateObject: (() => {
return false
})
}))What does it depend on??