为什么使用 React Hook 表单时表单测试失败？

Question

我正在使用 react-hook-form 构建一个表单。表单运行良好，但测试未通过。

当我不使用react-hook-form 并且jsut pass onSubmit <form onSubmit={onSubmit}> 时测试通过。当我使用 handleSubmit <form onSubmit={handleSubmit(onSubmit)}> 传递 onSubmit 时，它没有通过。

这是我的表格 App.js

import { useForm } from "react-hook-form";

export default function App({ onSubmit = (data) => console.log(data) }) {
  const { handleSubmit, register } = useForm();
  return (
    // <form onSubmit={onSubmit}>                  <--- This works
    // <form onSubmit={handleSubmit(onSubmit)}>    <--- This doesn't work
    <form onSubmit={handleSubmit(onSubmit)}>
      <input
        placeholder="Email"
        defaultValue=""
        key="email"
        {...register("email")}
      />
      <input
        placeholder="Password"
        defaultValue=""
        key="password"
        {...register("password")}
      />
      <input type="submit" value="submit" />
    </form>
  );
}

这是我为它编写的测试 App.test.js

import { render, screen } from "@testing-library/react";
import App from "./App";
import userEvent from "@testing-library/user-event";

test("email and password field are clear for submit", async () => {
  const handleSubmit = jest.fn();

  render(<App onSubmit={handleSubmit} />);

  userEvent.type(screen.getByPlaceholderText(/email/i), "test@example.com");
  userEvent.type(screen.getByPlaceholderText(/password/i), "password");
  userEvent.click(screen.getByText(/submit/i));

  expect(handleSubmit).toHaveBeenCalledTimes(1);
});

工作代码也可以在https://codesandbox.io/s/react-hook-form-testing-olo4i获得

Answer 1

handleSubmit 在签名下方，如您所见，它的返回值是一个 promise。它是异步的。

这意味着像这样调用它handleSubmit(onSubmit)(e) 将返回一个承诺。

type UseFormHandleSubmit<TFieldValues extends FieldValues> = <TSubmitFieldValues extends FieldValues = TFieldValues>(onValid: SubmitHandler<TSubmitFieldValues>, onInvalid?: SubmitErrorHandler<TFieldValues>) => (e?: React.BaseSyntheticEvent) => Promise<void>;

你需要使用waitFor的RTL：

import { render, screen, waitFor } from "@testing-library/react";
import App from "./App";
import userEvent from "@testing-library/user-event";

test("email and password field are clear for submit", async () => {
  const handleSubmit = jest.fn();

  render(<App onSubmit={handleSubmit} />);

  userEvent.type(screen.getByPlaceholderText(/email/i), "test@example.com");
  userEvent.type(screen.getByPlaceholderText(/password/i), "password");
  userEvent.click(screen.getByText(/submit/i));

  await waitFor(() => {
    expect(handleSubmit).toHaveBeenCalledTimes(1);
  }) 
});

如果不等待异步代码完成，它可能会在断言结束后执行。

Codesandbox

参考source code