[英]Waiting for two separate promises to resolve so state is updated
所以我正在测试一个改变状态的反应组件按钮点击。 在呈现组件时,我需要一个承诺来解决,以便呈现按钮并因此可点击。 我通过在组件状态更新时将按钮单击放置在 setTimeout 内来完成此操作。 但是,在单击按钮后,由于要解决承诺,需要更新组件状态。 下面我举个例子
class App extends component {
constructor(props){
this.state ={
hasError = false;
loading = true;
}
}
componentdidMount(){
this.apiGetFunc();
apiGetFunc(){
this.setState({hasError: false});
this.setState({loading = false});
}
onClickFunc{
this.middleWareCalltoAPI.then(
respone =>{ this.setState({hasError: false})},
errorRespone =>{ this.setState({hasError = true})};
)
}
renderer(){
return (
<Card>
{!this.state.hasError && !this.state.loading && (
<div>
<Button>
onClick = {this.onClickfunc}
</Button>
</div>
</Card>
)}
)
}
现在这是我的测试的样子
test("Save user permissions", done => {
mock.onGet("anAPI.php").reply(200, mockData); //THIS IS NEEDED TO RENDER THE BUTTON
const wrapper = shallow(<App />);
setTimeout(() => {
wrapper.find("Button").simulate("click"); //THIS CLICK SHOULD CHANGE hasError to true
expect(wrapper.state.hasError).toEqual(true) //THIS FAILS
done();
}, 0);
});
我试过嵌套 setTimeouts 以便点击的承诺可以解决,但这似乎不起作用。 我试图尽可能地精简我的代码,以便它具有可读性。 如果您需要我提供更多背景信息,请告诉我。
编辑:使代码更接近我实际拥有的
上面的示例代码中有很多错误,我强烈建议您在尝试继续之前花一些时间做一些简单的 React 教程。
尽管如此,这里有一个工作示例......
工作示例: https : //codesandbox.io/s/xj53m8lwvz (您可以通过单击屏幕左下角附近的“ Tests
选项卡来运行测试)
api/fakeAPI.js
const data = [
{
userId: 1,
id: 1,
title: "delectus aut autem",
completed: false
},
{
userId: 1,
id: 2,
title: "quis ut nam facilis et officia qui",
completed: false
},
{
userId: 1,
id: 3,
title: "fugiat veniam minus",
completed: false
},
{
userId: 1,
id: 4,
title: "et porro tempora",
completed: true
},
{
userId: 1,
id: 5,
title: "laboriosam mollitia et enim quasi adipisci quia provident illum",
completed: false
}
];
export const fakeAPI = {
failure: () =>
new Promise((resolve, reject) => {
setTimeout(() => {
reject("No data was found!");
}, 1000);
}),
success: () =>
new Promise(resolve => {
setTimeout(() => {
resolve(data);
}, 1000);
})
};
组件/应用程序/App.js
import React, { Component } from "react";
import ShowData from "../ShowData/showData";
import ShowError from "../ShowError/showError";
import { fakeAPI } from "../../api/fakeAPI";
export default class App extends Component {
state = {
data: [],
hasError: "",
isLoading: true
};
componentDidMount = () => {
this.fetchData();
};
fetchData = () => {
fakeAPI
.success()
.then(data => this.setState({ isLoading: false, data: data }))
.catch(err => this.setState({ isLoading: false, hasError: err }));
};
handleClick = () => {
this.setState({ isLoading: true, data: [] }, () => {
fakeAPI
.failure()
.then(res => this.setState({ isLoading: false, hasError: "" }))
.catch(err => this.setState({ isLoading: false, hasError: err }));
});
};
render = () => (
<div className="app-container">
{this.state.isLoading ? (
<ShowLoading />
) : this.state.hasError ? (
<ShowError error={this.state.hasError} />
) : (
<ShowData data={this.state.data} handleClick={this.handleClick} />
)}
</div>
);
}
components/App/__test__/App.test.js ( mountWrap
是一个自定义函数,您可以在test/utils/index.js
找到, WaitForExpect是一种更简单的方法,可以在 jest 的默认 5 秒超时内等待断言为true
)
import React from "react";
import { mountWrap } from "../../../test/utils";
import WaitForExpect from "wait-for-expect";
import App from "../App";
const initialState = {
data: [],
hasError: "",
isLoading: true
};
const wrapper = mountWrap(<App />, initialState);
describe("App", () => {
it("renders without errors", () => {
expect(wrapper.find("div.app-container")).toHaveLength(1);
});
it("initally shows that it's loading", () => {
expect(wrapper.state("isLoading")).toBeTruthy();
expect(wrapper.find("div.loading")).toHaveLength(1);
});
it("renders data and shows an Update button", async () => {
await WaitForExpect(() => {
wrapper.update();
expect(wrapper.state("isLoading")).toBeFalsy();
expect(wrapper.find("div.data")).toHaveLength(5);
expect(wrapper.find("button.update")).toHaveLength(1);
});
});
it("shows an error once the button has been clicked", async () => {
wrapper.find(".update").simulate("click");
await WaitForExpect(() => {
wrapper.update();
expect(wrapper.state("isLoading")).toBeFalsy();
expect(wrapper.state("hasError")).toBe("No data was found!");
expect(wrapper.find("div.error")).toHaveLength(1);
});
});
});
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