Reactjs 为什么我的酶测试失败了?
我有一个简单的测试,我想通过酵素/摩卡咖啡/柴。以下是错误:Reactjs 为什么我的酶测试失败了?,reactjs,mocha.js,chai,enzyme,Reactjs,Mocha.js,Chai,Enzyme,我有一个简单的测试,我想通过酵素/摩卡咖啡/柴。以下是错误: 1) <PostList /> should have a container for holding posts: TypeError: Cannot read property 'length' of undefined at PostList.render (D:/mydocs/webdev/gitprojs/ReactBlogFinal/views/PostList/PostList.js
1) <PostList /> should have a container for holding posts:
TypeError: Cannot read property 'length' of undefined
at PostList.render (D:/mydocs/webdev/gitprojs/ReactBlogFinal/views/PostList/PostList.jsx:13:9)
at node_modules\react-test-renderer\lib\shallow\ReactCompositeComponent.js:795:21
at measureLifeCyclePerf (node_modules\react-test-renderer\lib\shallow\ReactCompositeComponent.js:75:12)
at ShallowComponentWrapper._renderValidatedComponentWithoutOwnerOrContext (node_modules\react-test-renderer\lib\shallow\ReactCompositeComponent.js:794:25)
at ShallowComponentWrapper.performInitialMount (node_modules\react-test-renderer\lib\shallow\ReactCompositeComponent.js:361:30)
at ShallowComponentWrapper.mountComponent (node_modules\react-test-renderer\lib\shallow\ReactCompositeComponent.js:257:21)
at Object.mountComponent (node_modules\react-test-renderer\lib\shallow\ReactReconciler.js:45:35)
at ReactShallowRenderer._render (node_modules\react-test-renderer\lib\shallow\ReactShallowRenderer.js:138:23)
at _batchedRender (node_modules\react-test-renderer\lib\shallow\ReactShallowRenderer.js:85:12)
at Object.batchedUpdates (node_modules\react-test-renderer\lib\shallow\ReactDefaultBatchingStrategy.js:60:14)
at Object.batchedUpdates (node_modules\react-test-renderer\lib\shallow\ReactUpdates.js:97:27)
at ReactShallowRenderer.render (node_modules\react-test-renderer\lib\shallow\ReactShallowRenderer.js:112:18)
at ReactShallowRenderer.render (node_modules\enzyme\build\react-compat.js:171:37)
at node_modules\enzyme\build\ShallowWrapper.js:128:26
at ReactDefaultBatchingStrategyTransaction.perform (node_modules\react-test-renderer\lib\shallow\Transaction.js:143:20)
at Object.batchedUpdates (node_modules\react-test-renderer\lib\shallow\ReactDefaultBatchingStrategy.js:62:26)
at Object.batchedUpdates (node_modules\react-test-renderer\lib\shallow\ReactUpdates.js:97:27)
at ReactShallowRenderer.unstable_batchedUpdates (node_modules\react-test-renderer\lib\shallow\ReactShallowRenderer.js:130
1)应具有一个容器,用于固定立柱:
TypeError:无法读取未定义的属性“length”
在PostList.render(D:/mydocs/webdev/gitprojs/ReactBlogFinal/views/PostList/PostList.jsx:13:9)
在节点_modules\react test renderer\lib\shallow\ReactCompositeComponent.js:795:21
在measureLifeCyclePerf(节点\u modules\react test renderer\lib\shall\ReactCompositeComponent.js:75:12)
在ShallowComponentRapper.\u RenderValidatedComponent,没有自己的或上下文(节点\u modules\react test renderer\lib\shallow\reactComponent.js:794:25)
在ShallowComponentWrapper.performInitialMount(节点\u modules\react test renderer\lib\shallow\ReactCompositeComponent.js:361:30)
在ShallowComponentWrapper.mountComponent(节点\u modules\react test renderer\lib\shallow\ReactCompositeComponent.js:257:21)
在Object.mountComponent(node_modules\react test renderer\lib\shallow\ReactReconciler.js:45:35)
在ReactShallowRenderer.\u渲染(节点\u模块\react测试渲染器\lib\shallow\ReactShallowRenderer.js:138:23)
在_batchedRender(节点_modules\react test renderer\lib\shall\reactshallwrender.js:85:12)
在Object.batchedUpdate(node_modules\react test renderer\lib\shallow\ReactDefaultBatchingStrategy.js:60:14)
在Object.batchedUpdate(node_modules\react test renderer\lib\shall\ReactUpdates.js:97:27)
在reactshallwrender.render(节点\u modules\react test renderer\lib\shall\reactshallwrender.js:112:18)
在ReactShallWrender.render(节点\u modules\enzyme\build\react compat.js:171:37)
在节点_modules\enzyme\build\shallowRapper.js:128:26
在ReactDefaultBatchingStrategyTransaction.perform(节点\u modules\react test renderer\lib\shallow\Transaction.js:143:20)
在Object.batchedUpdate(node_modules\react test renderer\lib\shallow\ReactDefaultBatchingStrategy.js:62:26)
在Object.batchedUpdate(node_modules\react test renderer\lib\shall\ReactUpdates.js:97:27)
在reactshallwrender.js中,不稳定的批处理更新(节点\u modules\react test renderer\lib\shall\reactshallwrender.js:130
这是测试。我只是测试一下div是否存在:
import React from 'react';
import { mount, shallow, render } from 'enzyme';
import { expect } from 'chai';
import PostList from './PostList';
describe('<PostList />', () => {
it('should have a container for holding posts', () => {
const wrapper = shallow(<PostList />);
expect(wrapper.find('div')).to.have.length(1);
});
});
从“React”导入React;
从“酶”导入{mount,shallow,render};
从“chai”导入{expect};
从“/PostList”导入PostList;
描述(“”,()=>{
它('应该有一个用来装柱子的容器',()=>{
常量包装器=浅();
expect(wrapper.find('div')).to.have.length(1);
});
});
这是一个组件。这个组件将是一个博客文章的容器,if语句测试posts对象的长度,如果它通过,我的post div将开始生成。所以我知道这些文章一开始是未定义的。在React中,在呈现方法中使用这样的逻辑是一种不好的做法吗?或者这是t上的一个问题他站在哪一边
import React from 'react';
export default class PostList extends React.Component {
render() {
const posts = this.props.posts;
let postDivs;
if (posts.length !== 0) {
postDivs = posts.map(post => (
<div className="post-item" key={post._id}>
<h2 className="post-title">{post.title}</h2>
<h3 className="post-date">{post.date}</h3>
<h3 className="author">{post.author}</h3>
<p className="body">{post.body}</p>
</div>
));
console.log(postDivs);
}
return (
<div className="post-container">
{postDivs}
</div>
);
}
}
从“React”导入React;
导出默认类PostList扩展React.Component{
render(){
const posts=this.props.posts;
让postDivs;
如果(posts.length!==0){
postDivs=posts.map(post=>(
{post.title}
{发布日期}
{post.author}
{post.body}
));
console.log(postDivs);
}
返回(
{postDivs}
);
}
}
您在呈现帖子列表时没有定义帖子(在道具上)
const wrapper=shallow()
因此,this.props.posts是未定义的,您正在尝试从未定义的变量读取属性(长度)
1) <PostList /> should have a container for holding posts:
TypeError: Cannot read property 'length' of undefined
1)应具有一个容器,用于固定立柱:
TypeError:无法读取未定义的属性“length”
这会导致异常,并且您的测试失败您正在呈现PostList,而没有定义posts(在props上)
const wrapper=shallow()
因此,this.props.posts是未定义的,您正在尝试从未定义的变量读取属性(长度)
1) <PostList /> should have a container for holding posts:
TypeError: Cannot read property 'length' of undefined
1)应具有一个容器,用于固定立柱:
TypeError:无法读取未定义的属性“length”
这导致异常,并且您的测试失败
此.props.posts
未定义undefined
没有长度-只有字符串和数组有长度(或某些具有自定义getter的对象)
您需要
PostList.defaultProps={posts:[]}
或者在propTypes
中要求它,或者将巡更测试作为
编写,或者将呈现语句作为if(posts!==undefined&&posts.length!==0){
或const{posts=[]}=this.props
-自己选择。this.props.posts
是未定义的
未定义的
没有长度-只有字符串和数组有长度(或某些具有自定义getter的对象)
您需要PostList.defaultProps={posts:[]}
或者在propTypes
中要求它,或者将tour test作为
编写,或者将render语句作为if(posts!==undefined&&posts.length!==0){
或const{posts=[]}=this.props
-请选择