Reactjs 类型错误：'；未定义'；不是对象（评估'；this.props.people.map'；）

运行测试用例时，“未定义”不是对象错误。这是实际的代码

class People extends React.Component{
    displayAlert (email){
       alert(email);
 }

render (){
 return (
    <div>{
        <ul key = {this.props.id}>
            <li>
                <button onClick= {this.displayAlert.bind(this, this.props.email)}>{this.props.lastName + ', ' + this.props.firstName}</button>
            </li>
        </ul>}
    </div>
  );
 }
}

class PersonList extends React.Component{
render () {
 /* people is an array of people*/
  var items = this.props.people.map( function ( item ){
    return <People id = {item.id} email = {item.email} firstName = {item.firstName} lastName = {item.lastName}> </People>
});

return (
    <div> {items} </div>
  )
 }
}
React.render( <PersonList people={ people } />, el );

PhantomJS 1.9.8（Windows 7 0.0.0）人员列表中的每个失败人员都有一个实例 AssertionError:应为1等于2

我有另一个测试用例来确保没有额外的元素。但它也失败了。下面是测试用例和错误

it( `doesn't have extra elements`, () => {
    expect( domnode.querySelectorAll( '> :not( ul )' ).length ).to.equal( 0 );
   expect( domnode.querySelectorAll( '> ul > :not( li )' ).length ).to.equal( 0 );

} );

PhantomJS 1.9.8（Windows 7 0.0.0）人员列表没有其他元素失败

---

抛出了DomeException“Error:SYNTAX\u ERR:DOM Exception 12”，抛出一个错误：）

它还应该告诉您错误发生的确切位置。您能告诉我们如何设置测试数据和测试吗？

it( `doesn't have extra elements`, () => {
    expect( domnode.querySelectorAll( '> :not( ul )' ).length ).to.equal( 0 );
   expect( domnode.querySelectorAll( '> ul > :not( li )' ).length ).to.equal( 0 );

} );