状态更改后，React Test 无法按文本找到元素

Question

我有一个 LoginForm 组件，它接受 login 回调并呈现登录表单。当 login returns 拒绝承诺时，消息将显示在组件中。这是我要测试的行为。

我正在使用 jest、enzyme 和 @testing-library/react 的 create-react-app 环境。

我已经在 UI（浏览器）中手动测试了该组件并确保其正常工作并显示了消息，但测试不工作并且最后一个断言失败：

TestingLibraryElementError: Unable to find an element with the text: There was an error. 
This could be because the text is broken up by multiple elements. 
In this case, you can provide a function for your text matcher to make your matcher more flexible.

我检查了在浏览器中呈现时的消息，它显示为文字“出现错误”，中间没有任何元素。仅由样式组件包裹。我无法让测试正常工作谁能帮忙？

我的测试如下：

    it("should display error text in login form when login fails", async () => {
        const errorText = "There was an error";
        const login = jest.fn(() => {
            return Promise.reject(errorText);
        });

        const result = render(<LoginForm login={login} />);


        const form = result.container.querySelector("form");
        const email = await result.findByLabelText("Email");
        const password = await result.findByLabelText("Password");

        fireEvent.change(email, {target: {name: "email", value: "1"}});
        fireEvent.change(password, {target: {name: "password", value: "1"}});

        expect(form).toBeDefined();

        fireEvent.submit(form!, {});

        expect(login).toBeCalledTimes(1);
 
        // This assertion fails
        expect(result.getByText(errorText)).toBeInTheDocument();
    });

我的组件渲染如下：

render() {
        const {error, email, password} = this.state;

        return (
            <Form noValidate onSubmit={this.onSubmit}>
                <InputWrapper>
                    <Label htmlFor="email">Email</Label>
                    <InputEmail id="email" name="email" value={email} onChange={this.onChange}/>
                </InputWrapper>

                <InputWrapper>
                    <Label htmlFor="password">Password</Label>
                    <InputPassword id="password" name="password" value={password} onChange={this.onChange}/>
                </InputWrapper>

                // LoginError is a styled-component
                {error && (<LoginError>{error}</LoginError>)}

                {this.props.children}

                <Button>Login</Button>
            </Form>
        );


    }

Answer 1

尝试在 fireEvent.submit(form!, {}) 之后使用 wait 或 wait For 方法；等待 promise 解决并重新渲染。

参考：testing-library.com/docs/dom-testing-library/api-async#waitfor

状态更改后，React Test 无法按文本找到元素

React Test doesnt find element by text after state change

reactjs

jestjs

enzyme

react-testing-library

react-testing