Prueba fallida: Nada fue devuelto de render. idéntica prueba pasa, la única diferencia con el error de la prueba es el uso de initialEntries

Question 1

Estoy tratando de probar si mis rutas son de trabajo, la primera prueba que pasa cuando me pruebe el defecto "/" de la ruta, sin embargo, la segunda prueba no pasa. la única diferencia es que en la segunda prueba de la initialEntries={['/register']} se introduce, y como resultado de la segunda prueba falla por esta razón:

"Inicio de sesión(...): Nada fue devuelto de render. Esto generalmente significa que una instrucción return es la que falta. O, para no representar nada, se devuelve null."

He comprobado la otra pregunta con respecto a esto, pero ellos no parecen coincidir con mi problema en particular

este es mi app.js que contiene todas las rutas

import React from 'react';
import {BrowserRouter as Router, Route, Switch} from 'react-router-dom'
import PrivateRoute from './components/PrivateRoute';
import Login from './components/LoginRegister/Login';
import Dashboard from './components/Dashboard/Dashboard';
import Register from './components/LoginRegister/Register';
import PageNotFound from './components/Pages/PageNotFound';
import Header from './components/LoginRegister/Header';
function App() {

  return (
    <Router>
      <div className="main-container">
          <div className="Route-container">
          <Header/>
              <Switch>
                <PrivateRoute exact path = '/dashboard' component = {Dashboard}></PrivateRoute> 
                <Route exact path = '/' component = {Login} />
                <Route exact path = '/test' component = {Dashboard} />
                <Route exact path = '/register' component = {Register} /> 
                <Route component = {PageNotFound} /> 
              </Switch>
          </div>
        </div>
    </Router>
  );
}

export default App;

Este es mi App.test.js

import React from 'react'
import { render, screen } from '@testing-library/react';
import { MemoryRouter } from 'react-router';
import App from "./App";
import Dashboard from './components/Dashboard/Dashboard'; 
import Header from './components/LoginRegister/Header';
import Login from './components/LoginRegister/Login';
import Register from './components/LoginRegister/Register';
import PageNotFound from './components/Pages/PageNotFound';
import '@testing-library/jest-dom/extend-expect';

jest.mock('./components/Dashboard/Dashboard');
jest.mock('./components/LoginRegister/Login');
jest.mock('./components/LoginRegister/Register');
jest.mock('./components/Pages/PageNotFound');
jest.mock('./components/LoginRegister/Header');

describe("App component", () =>{
    it("renders page header and login component on default route", ()=>{
        Header.mockImplementation(()=> <div>HeaderMock</div>);
        Login.mockImplementation(()=> <div>LoginMock</div>);

        render(
          <MemoryRouter>
            <App />
          </MemoryRouter>
        );
        
        expect(screen.getByText("HeaderMock")).toBeInTheDocument();
        expect(screen.getByText("LoginMock")).toBeInTheDocument();
    });

    it("Renders page header and Register component on Register route", ()=>{
      Header.mockImplementation(()=> <div>HeaderMock</div>);
      Register.mockImplementation(()=> <div>RegisterMock</div>);

      render(
        <MemoryRouter initialEntries={['/register']}>
            <App />
        </MemoryRouter>
      );
      
      expect(screen.getByText("HeaderMock")).toBeInTheDocument();
      expect(screen.getByText("RegisterMock")).toBeInTheDocument();
  });
});

Este es el Register.js componente

import React from 'react'
import { useState } from 'react';
import { Link, useHistory } from 'react-router-dom';

const initialState = {
    credentials: {
    name: '',
    username: '',
    password: ''
  }
}

function Register() {
    const [state, setState] = useState(initialState)
    const history = useHistory()

    function goToLogin () {
        history.push('/')
    }

function handleChange(e) {
    setState({
        credentials: {
            ...state.credentials,
            [e.target.name]: e.target.value
        }
    })
   }
    return (
        <div className = "main-container">
            
            <div className = "middle-section">
                
                <div className= "login-section">
                
                    <div className = "selection login-flex-item">
                        Already a member? &nbsp;
                        <Link to ='/' className = 'select-logreg'>Login</Link>
                    </div>

                    <form className = 'login-flex-item' onSubmit = {goToLogin}>
                
                        <input className = 'form-item'
                            type = 'text'
                            name = 'name'
                            placeholder = "Enter Name"
                            value = {state.credentials.name}
                            onChange ={handleChange}
                        />
                        <input className = 'form-item'
                            type = 'text'
                            name = 'username'
                            placeholder = "Username"
                            value = {state.credentials.username}
                            onChange ={handleChange}
                        />
                        <input className = 'form-item'
                            type="password"
                            name="password"
                            placeholder = "Password"
                            value={state.credentials.password}
                            onChange={handleChange}
                        />
                        <button className = 'form-item btn'>Sign Up</button>
                    </form>
                </div>
            </div>
        </div>
    );
};

export default Register;

y esta es la prueba de errores descripción de me estoy haciendo cualquier ayuda sería impresionante que he estado mirando esto durante horas y no parecen encontrar una solución.

 FAIL  src/App.test.js
  App component
    √ renders page header and login component on default route (33 ms)
    × Renders page header and Register component on Register route (198 ms)

  ● App component › Renders page header and Register component on Register route

    Login(...): Nothing was returned from render. This usually means a return statement is missing. Or, to render nothing, return null.

      35 |       Register.mockImplementation(()=> <div>RegisterMock</div>);
      36 |
    > 37 |       render(
         |       ^
      38 |         <MemoryRouter initialEntries={['/register']}>
      39 |             <App />
      40 |         </MemoryRouter>

      at reconcileChildFibers (node_modules/react-dom/cjs/react-dom.development.js:14169:23)
      at reconcileChildren (node_modules/react-dom/cjs/react-dom.development.js:16990:28)
      at mountIndeterminateComponent (node_modules/react-dom/cjs/react-dom.development.js:17890:5)
      at beginWork (node_modules/react-dom/cjs/react-dom.development.js:19049:16)
      at HTMLUnknownElement.callCallback (node_modules/react-dom/cjs/react-dom.development.js:3945:14)
      at HTMLUnknownElement.callTheUserObjectsOperation (node_modules/jsdom/lib/jsdom/living/generated/EventListener.js:26:30)
      at innerInvokeEventListeners (node_modules/jsdom/lib/jsdom/living/events/EventTarget-impl.js:338:25)
      at invokeEventListeners (node_modules/jsdom/lib/jsdom/living/events/EventTarget-impl.js:274:3)
      at HTMLUnknownElementImpl._dispatch (node_modules/jsdom/lib/jsdom/living/events/EventTarget-impl.js:221:9)
      at HTMLUnknownElementImpl.dispatchEvent (node_modules/jsdom/lib/jsdom/living/events/EventTarget-impl.js:94:17)
      at HTMLUnknownElement.dispatchEvent (node_modules/jsdom/lib/jsdom/living/generated/EventTarget.js:231:34)
      at Object.invokeGuardedCallbackDev (node_modules/react-dom/cjs/react-dom.development.js:3994:16)
      at invokeGuardedCallback (node_modules/react-dom/cjs/react-dom.development.js:4056:31)
      at beginWork$1 (node_modules/react-dom/cjs/react-dom.development.js:23964:7)
      at performUnitOfWork (node_modules/react-dom/cjs/react-dom.development.js:22779:12)
      at workLoopSync (node_modules/react-dom/cjs/react-dom.development.js:22707:5)
      at renderRootSync (node_modules/react-dom/cjs/react-dom.development.js:22670:7)
      at performSyncWorkOnRoot (node_modules/react-dom/cjs/react-dom.development.js:22293:18)
      at scheduleUpdateOnFiber (node_modules/react-dom/cjs/react-dom.development.js:21881:7)
      at updateContainer (node_modules/react-dom/cjs/react-dom.development.js:25482:3)
      at node_modules/react-dom/cjs/react-dom.development.js:26021:7
      at unbatchedUpdates (node_modules/react-dom/cjs/react-dom.development.js:22431:12)
      at legacyRenderSubtreeIntoContainer (node_modules/react-dom/cjs/react-dom.development.js:26020:5)
      at Object.render (node_modules/react-dom/cjs/react-dom.development.js:26103:10)
      at node_modules/@testing-library/react/dist/pure.js:101:25
      at batchedUpdates$1 (node_modules/react-dom/cjs/react-dom.development.js:22380:12)
      at act (node_modules/react-dom/cjs/react-dom-test-utils.development.js:1042:14)
      at render (node_modules/@testing-library/react/dist/pure.js:97:26)
      at Object.<anonymous> (src/App.test.js:37:7)

Question 2

A partir de la doc <Router>:

El común de la interfaz de bajo nivel para todos los router de los componentes. Normalmente en las aplicaciones de uso uno de los de alto nivel de los routers en su lugar:

<BrowserRouter>

<HashRouter>

<MemoryRouter>

<NativeRouter>

<StaticRouter>

El problema es <BrowserRouter> componente está envuelto en <MemoryRouter> como este:

<MemoryRouter>
  <BrowserRouter>
    <Switch>
     ....
    </Switch>
  </BrowserRouter>
</MemoryRouter>

Esto le dará la location de <BrowserRouter>será:

location:  { pathname: '/', search: '', hash: '', state: undefined }

Usted debe dividir el <Switch> y a sus hijos como un componente independiente como Routes:

import React from 'react';
import { BrowserRouter as Router, Route, Switch, useLocation } from 'react-router-dom';

const Login = () => <div>login</div>;
const Register = () => <div>Register</div>;

export const Routes = () => {
  const location = useLocation();
  console.log('location: ', location);
  return (
    <Switch>
      <Route exact path="/" component={Login} />
      <Route exact path="/register" component={Register} />
    </Switch>
  );
};

function App() {
  return (
    <Router>
      <Routes />
    </Router>
  );
}

export default App;

Así que usted puede utilizar Routes con <MemoryRouter> para las pruebas:

import React from 'react';
import { MemoryRouter } from 'react-router-dom';
import { render, screen } from '@testing-library/react';
import '@testing-library/jest-dom/extend-expect';
import { Routes } from './app';

describe('App component', () => {
  it('renders page header and login component on default route', () => {
    render(
      <MemoryRouter>
        <Routes />
      </MemoryRouter>
    );
    expect(screen.getByText('login')).toBeInTheDocument();
  });

  it('Renders page header and Register component on Register route', () => {
    render(
      <MemoryRouter initialEntries={['/register']}>
        <Routes />
      </MemoryRouter>
    );
    expect(screen.getByText('Register')).toBeInTheDocument();
  });
});

el resultado de la prueba:

 PASS  examples/70090905/app.test.tsx (8.087 s)
  App component
    ✓ renders page header and login component on default route (45 ms)
    ✓ Renders page header and Register component on Register route (3 ms)

  console.log
    location:  {
      pathname: '/',
      search: '',
      hash: '',
      state: undefined,
      key: 'zlnxcn'
    }

      at Routes (examples/70090905/app.tsx:9:11)

  console.log
    location:  {
      pathname: '/register',
      search: '',
      hash: '',
      state: undefined,
      key: '8z804n'
    }

      at Routes (examples/70090905/app.tsx:9:11)

Test Suites: 1 passed, 1 total
Tests:       2 passed, 2 total
Snapshots:   0 total
Time:        8.625 s, estimated 11 s

Para ilustrativos y los propósitos de la demostración, he quitado código innecesario.

Las versiones de los paquetes:

"react-router-dom": "^5.2.0"

slideshowp2 · Answer 1 · 2021-11-24T07:54:05

A partir de la doc <Router>:

El común de la interfaz de bajo nivel para todos los router de los componentes. Normalmente en las aplicaciones de uso uno de los de alto nivel de los routers en su lugar:

<BrowserRouter>

<HashRouter>

<MemoryRouter>

<NativeRouter>

<StaticRouter>

El problema es <BrowserRouter> componente está envuelto en <MemoryRouter> como este:

<MemoryRouter>
  <BrowserRouter>
    <Switch>
     ....
    </Switch>
  </BrowserRouter>
</MemoryRouter>

Esto le dará la location de <BrowserRouter>será:

location:  { pathname: '/', search: '', hash: '', state: undefined }

Usted debe dividir el <Switch> y a sus hijos como un componente independiente como Routes:

import React from 'react';
import { BrowserRouter as Router, Route, Switch, useLocation } from 'react-router-dom';

const Login = () => <div>login</div>;
const Register = () => <div>Register</div>;

export const Routes = () => {
  const location = useLocation();
  console.log('location: ', location);
  return (
    <Switch>
      <Route exact path="/" component={Login} />
      <Route exact path="/register" component={Register} />
    </Switch>
  );
};

function App() {
  return (
    <Router>
      <Routes />
    </Router>
  );
}

export default App;

Así que usted puede utilizar Routes con <MemoryRouter> para las pruebas:

import React from 'react';
import { MemoryRouter } from 'react-router-dom';
import { render, screen } from '@testing-library/react';
import '@testing-library/jest-dom/extend-expect';
import { Routes } from './app';

describe('App component', () => {
  it('renders page header and login component on default route', () => {
    render(
      <MemoryRouter>
        <Routes />
      </MemoryRouter>
    );
    expect(screen.getByText('login')).toBeInTheDocument();
  });

  it('Renders page header and Register component on Register route', () => {
    render(
      <MemoryRouter initialEntries={['/register']}>
        <Routes />
      </MemoryRouter>
    );
    expect(screen.getByText('Register')).toBeInTheDocument();
  });
});

el resultado de la prueba:

 PASS  examples/70090905/app.test.tsx (8.087 s)
  App component
    ✓ renders page header and login component on default route (45 ms)
    ✓ Renders page header and Register component on Register route (3 ms)

  console.log
    location:  {
      pathname: '/',
      search: '',
      hash: '',
      state: undefined,
      key: 'zlnxcn'
    }

      at Routes (examples/70090905/app.tsx:9:11)

  console.log
    location:  {
      pathname: '/register',
      search: '',
      hash: '',
      state: undefined,
      key: '8z804n'
    }

      at Routes (examples/70090905/app.tsx:9:11)

Test Suites: 1 passed, 1 total
Tests:       2 passed, 2 total
Snapshots:   0 total
Time:        8.625 s, estimated 11 s

Para ilustrativos y los propósitos de la demostración, he quitado código innecesario.

Las versiones de los paquetes:

"react-router-dom": "^5.2.0"

Prueba fallida: Nada fue devuelto de render. idéntica prueba pasa, la única diferencia con el error de la prueba es el uso de initialEntries

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