How to snapshot test connected component that wrapped with connected component? - reactjs

I need to ask about testing React using enzyme and jest. The case is I have a redux connected component wrapped by also connected component.
wrapper.js
import React from "react";
import { connect } from "react-redux";
import { state, actions } from "src/services/common-store/user";
function ApplicationLayout(props) {
return (
<div>
<h1>{props.title}</h1>
<div id="content">
{props.children}
</div>
</div>
);
}
export default connect(state, actions)(ApplicationLayout);
User.js
import React from "react";
import { connect } from "react-redux";
import { state, actions } from "src/services/common-store/user";
import ApplicationLayout from './ApplicationLayout';
function User(props) {
return (
<ApplicationLayout>
<h1>{props.user.name}</h1>
<img src={props.user.img} />
</ApplicationLayout>
);
}
export default connect(state, actions)(User);
in my test file, I already provided Provider with redux mock store.
User.test.js
import React from "react";
import { mount } from "enzyme";
import configureMockStore from "redux-mock-store";
import { Provider } from "react-redux";
import toJson from "enzyme-to-json";
import thunk from "redux-thunk";
import User from "./User.js";
// Mocking Redux store
const mockStore = configureMockStore([thunk]);
const store = mockStore({ title: "Application Layout", user: { name: "andri", img: "https://ava.com/img.jpg" } });
const setup = () => {
return mount(
<Provider store={store}>
<User />
</Provider>
);
};
describe("Test Component", () => {
let wrapper;
beforeEach(() => {
wrapper = setup();
});
describe("Components rendering", () => {
it("Should render without error and match snapshot", () => {
expect(toJson(wrapper)).toMatchSnapshot();
});
});
});
but I keep getting error said that props like title and user are undefined TypeError: Cannot read property 'user' of undefined. what can I do to address this?

Related

Failing to mock child react component in tests

There are a bunch of articles and examples about this one, but for some reason, nothing seems to work.
I have a react component that has a child component. And, for simplicity's sake, I want to mock the child component in the test.
The component looks like this:
...
import { ProjectTeam } from '../../assignment/project-team/component';
export const ProjectOverview: React.FC<ProjectOverviewProps> = ({ projectId }) => {
...
return (
<>
...
<Box flex={1}>
<ProjectTeam projectId={projectId} />
</Box>
...
</>
);
};
The ProjectTeam component:
export const ProjectTeam: React.FC<ProjectTeamProps> = ({ projectId }) => {
// just a standard component...
};
And here is the test:
import React from 'react';
import configureMockStore from 'redux-mock-store';
import { Provider } from 'react-redux';
import { render } from '#testing-library/react';
import { I18nextProvider } from 'react-i18next';
import { generateProject } from '../../testing/generators/project';
import { ProjectOverview } from './component';
import { NGStateProvider } from '../../react/providers/route-provider/component';
import { testAngularRouter } from '../../testing/testAngularRouter';
import { DefaultProjectCollection, DefaultUtilizationCollection } from '../store/model';
import { DefaultApaActionCollection } from '../../apa/model';
import i18n from '../../testing/i18n';
import thunk from 'redux-thunk';
describe('ProjectOverview', () => {
let mockStore = null;
const project = generateProject();
beforeEach(() => {
jest.mock('../../assignment/project-team/component', () => ({ ProjectTeam: 'ProjectTeam' }));
mockStore = configureMockStore([thunk])({
projects: { DefaultProjectCollection, ...{ entities: { [project.id]: project } } },
toolUtilizations: DefaultUtilizationCollection,
apaActions: DefaultApaActionCollection,
});
});
test('renders correctly', () => {
const { asFragment } = render(
<NGStateProvider router={testAngularRouter}>
<Provider store={mockStore}>
<I18nextProvider i18n={i18n}>
<ProjectOverview projectId={project.id} />
</I18nextProvider>
</Provider>
</NGStateProvider>,
);
expect(asFragment()).toMatchSnapshot();
});
});
My assumption, that jest.mock(...) should simply replace the child component in test mode. However, it does not. The whole component is trying to render as is.
Here is one of the articles I was referring to: https://thoughtbot.com/blog/mocking-react-components-with-jest
Try moving the jest.mock call outside. I would say right at the top, just before and outside the describe section.
Jest needs to know about mocked component before it starts executing the test file in question.
The article which you reference, has this info,
Alternatively, you can put it within a __mocks__ folder next to the component if that is your preference.

How Can I test react redux component by enzyme?

I have to do it a few simple React Enzyme tests. I want to check if component is rendered.
import React from 'react';
import { shallow } from 'enzyme';
import ConnSearch from './ConnSearch';
it('renders without errors', () => {
const component = shallow(<ConnSearch />);
console.log(component.debug());
});
I have results: Could not find "store" in the context of "Connect(ConnSearch)". Either wrap the root component in a , or pass a custom React context provider to a
nd the corresponding React context consumer to Connect(ConnSearch) in connect options.
My ConnSearch Component:
import React, { Component } from 'react';
import {fetchRoadDetails, fetchUserPoints} from "../../actions";
import {connect} from "react-redux";
import RoadTable from "../../components/RoadTable/RoadTable";
import RoadForm from "../../components/RoadTable/RoadForm";
import style from './ConnSearch.module.scss'
import {getPoints} from "../../reducers";
class ConnSearch extends Component {
constructor(props){
super(props);
this.state = {
};
}
componentDidMount() {
this.props.fetchUserPoints(this.props.userLogin);
}
render() {
return (
<div className={style.wrapper}>
<RoadForm />
<div className={style.tableWrapper} >
<RoadTable/>
</div>
</div>
);
}
}
const mapDispatchToProps=dispatch=>({
fetchRoadDetails:()=>dispatch(fetchRoadDetails()),
fetchUserPoints:(user)=>dispatch(fetchUserPoints(user)),
});
const mapStateToProps = (state) => {
return {
roads: state.road,
points:getPoints(state),
userLogin: state.userLogin,
};
};
export default connect(mapStateToProps,mapDispatchToProps)(ConnSearch);
How can I do this test ? I've never done that before.
Unfortunately, when I wrap it in a provider:
it('renders without errors', () => {
const component = shallow( <Provider store={store}><ConnSearch/></Provider>);
console.log(component.debug());
});
I got this:
console.log src/views/ConnectionSearch/ConnSearch.test.js:11
<ContextProvider value={{...}}>
<Connect(ConnSearch) />
</ContextProvider>
I want ConnSearch render structure.

Field must be inside a component decorated with reduxForm(), Error in test file

When i run my tests, i get the error:
Field must be inside a component decorated with reduxForm()
I am mocking a store, so i would think that would take care of injecting redux on the test but, i'm not really sure.
Inside appointments.js I have a component that has a redux form
import React from 'react';
... other imports
import configureMockStore from 'redux-mock-store';
import { mount } from 'enzyme';
import expect from 'expect';
import { Provider } from 'react-redux';
import { IntlProvider } from 'react-intl';
import LoginSection from '../User/LoginSection';
import AppointmentsContainer from './AppointmentsContainer';
import Appointments from './Appointments';
import AppointmentStatus from .../Layout/AppointmentStatus/AppointmentStatusContainer';
jest.mock('./Appointments');
jest.mock('../User/LoginSection');
jest.mock('../Layout/AppointmentStatus/AppointmentStatusContainer');
const store = configureMockStore()({
form: 'Appointments',
});
const setup = (newProps) => {
const props = {
handleSubmit: jest.fn(),
},
form: 'appointmentsContainer',
locale: 'en',
...newProps,
};
const root = mount(
<Provider store={store}>
<IntlProvider {...props}>
<AppointmentsContainer {...props} />
</IntlProvider>
</Provider>
,
);
const wrapper = root.find(Appointments);
return {
root,
wrapper,
props,
};
};
describe('AppointmentsContainer', () => {
beforeEach(() => {
store.clearActions();
});
Any idea how can i fix this?

Why enzyme tests did not work in React.js?

I am using Enzyme tests within Create-React-App. In shallow rendering it works fine, but mount rendering throws error:
TypeError: Cannot read property 'favorites' of undefined
Test file looks like this:
import React, { Component } from "react";
import configureMockStore from "redux-mock-store";
import { shallow, mount } from "enzyme";
import { Provider } from "react-redux";
import Favorites from "../Landing/Favorites";
const mockStore = configureMockStore();
const store = mockStore({});
function setup() {
const props = {
favorites: 42
};
const wrapper = mount(
<Provider store={store}>
<Favorites {...props} />
</Provider>
);
return {
props,
wrapper
};
}
describe("Favorites component", () => {
const { wrapper } = setup();
it("should render list of favorites cards", () => {
expect(wrapper.prop("favorites")).toEqual(42);
});
});
Why did it happen?
.prop works different in mount and shallow. You can check the docs.
http://airbnb.io/enzyme/docs/api/ReactWrapper/prop.html
http://airbnb.io/enzyme/docs/api/ShallowWrapper/prop.html
When using mount, you can directly render Favorites component.
mount(<Favorites {...props} />)

TypeError: dispatch is not a function when testing with react-create-app jest and enzyme

I'm trying to setup testing on a new project created with react-create-app. Which now seems to be using React 16 and Jest 3 (which supposedly had some breaking changes, or maybe that was enzime). I'm getting an error similar to this post TypeError: dispatch is not a function when I try to test a method using JEST
TypeError: dispatch is not a function
at App.componentDidMount (src/components/App.js:21:68)
import React from 'react';
import { Provider } from 'react-redux';
import { mount } from 'enzyme';
import { App } from '../components/App';
import configureStore from '../state/store/configureStore';
window.store = configureStore({
slider: {
mainImageIndex: 0,
pageNum: 1,
perPage: 4,
},
});
const appTest = (
<Provider store={window.store}>
<App />
</Provider>
);
describe('App', () => {
it('should render without crashing', () => {
mount(appTest);
});
});
Originally I just tried to do this:
import React from 'react';
import { mount } from 'enzyme';
import { App } from '../components/App';
describe('App', () => {
it('should render without crashing', () => {
mount(<App />);
});
});
Which threw this error
Invariant Violation: Could not find "store" in either the context or props of "Connect(Form(SearchForm))". Either wrap the root component in a , or explicitly pass "store" as a prop
Code for App.js:
import React, { Component } from 'react';
import { connect } from 'react-redux';
import { searchPhotos } from '../state/actions/searchPhotos';
import { setMainImageIndex, setFirstPage } from '../state/actions/slider';
import Slider from './Slider';
import SearchForm from './SearchForm';
import Error from './Error';
import '../styles/App.css';
export class App extends Component {
componentDidMount() {
const { dispatch } = this.props;
dispatch(searchPhotos(window.store));
}
searchPhotosSubmit = () => {
const { dispatch } = this.props;
dispatch(setFirstPage());
dispatch(setMainImageIndex(0));
dispatch(searchPhotos(window.store));
}
render() {
const { fetchError } = this.props;
return (
<div className="App">
<header className="App-header">
<h1 className="App-title">Flickr Slider in React.js</h1>
<SearchForm onSubmit={this.searchPhotosSubmit} />
</header>
{!fetchError ? <Slider /> : <Error />}
</div>
);
}
}
export default connect(state => ({
fetchError: state.fetchError,
form: state.form,
slider: state.slider,
}))(App);
Please not that you export both presentational component (as named export) and container component (as default export) in App.js. Then in your tests you import and use the presentational component using:
import { App } from '../components/App';
but you should import connected container component instead using:
import App from '../components/App'; // IMPORTANT! - no braces around `App`
Since you're using component that is not connected to Redux store dispatch prop is not injected as prop. Just use correct import and it should work.
For more details about importing default and named exports please check this doc. About presentational and container components you can read here.

Resources