[英]How correctly write Jest test for avoid act() warning?
useEffect 通常使用 Promises 來更新 state。
此更新會開玩笑地發出長時間警告: Warning: An update to null inside a test was not wrapped in act(...).
對於這種情況如何正確編寫 Jest Test?
活生生的例子,可重現的例子:
https://codesandbox.io/s/jest-test-for-useeffect-with-promises-spieq?file=/index.test.js
index.test.js
import React from "react";
import Hello from "./Hello";
import { create, act } from "react-test-renderer";
it("works", () => {
let root;
act(() => {
root = create(<Hello />);
});
// console.log("From test:", );
let repr = JSON.stringify(root.toJSON());
expect(repr).toBe('{"type":"span","props":{},"children":["Hello! "]}');
});
你好.js
import React, { useState, useEffect } from "react";
export default () => {
const [count, setCount] = useState();
useEffect(() => {
Promise.resolve({}).then(() => setCount(4));
}, []);
return <span>Hello! {count}</span>;
};
更新1:
其中一個propasal的結果相同:
看起來這個示例工作正常
import React from "react";
import Hello from "./Hello";
import { render, screen, waitFor } from "@testing-library/react";
import "@testing-library/jest-dom";
it("works", () => {
render(<Hello />);
return waitFor(() => screen.getByText("Hello! 4"));
// expect(baseElement.toBeTruthy();
});
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