OpenMediaCenter/src/pages/HomePage/HomePage.test.js

import {shallow} from "enzyme";
import React from "react";
import HomePage from "./HomePage";
import VideoContainer from "../../elements/VideoContainer/VideoContainer";

function prepareFetchApi(response) {
    const mockJsonPromise = Promise.resolve(response);
    const mockFetchPromise = Promise.resolve({
        json: () => mockJsonPromise,
    });
    return (jest.fn().mockImplementation(() => mockFetchPromise));
}

function prepareFailingFetchApi() {
    const mockFetchPromise = Promise.reject("myreason");
    return (jest.fn().mockImplementation(() => mockFetchPromise));
}

describe('<HomePage/>', function () {
    it('renders without crashing ', function () {
        const wrapper = shallow(<HomePage/>);
        wrapper.unmount();
    });

    it('ckeck default tag click events', function () {
        const wrapper = shallow(<HomePage/>);
        global.fetch = prepareFetchApi({});

        expect(global.fetch).toBeCalledTimes(0);
        // click every tag button
        wrapper.find("Tag").map((i) => {
            i.simulate("click");
        });
        expect(global.fetch).toBeCalledTimes(4);
    });

    it('test data insertion', function () {
        const wrapper = shallow(<HomePage/>);

        expect(wrapper.find("VideoContainer")).toHaveLength(0);

        wrapper.setState({
            data: [
                {}, {}
            ]
        });

        // there shoud be loaded the Videocontainer element into dom after fetching videos correctly
        expect(wrapper.find("VideoContainer")).toHaveLength(1);
    });

    it('test title and nr insertions', function () {
        const wrapper = shallow(<HomePage/>);

        expect(wrapper.find("PageTitle").props().subtitle).toBe("All Videos - 0");

        wrapper.setState({
            tag: "testtag",
            selectionnr: 42
        });

        expect(wrapper.find("PageTitle").props().subtitle).toBe("testtag Videos - 42");
    });

    it('test search field', done => {
        global.fetch = prepareFetchApi([{}, {}]);

        const wrapper = shallow(<HomePage/>);

        wrapper.find('[data-testid="searchtextfield"]').simulate('change', {target: {value: 'testvalue'}});
        wrapper.find('[data-testid="searchbtnsubmit"]').simulate("click");

        process.nextTick(() => {
            // state to be set correctly with response
            expect(wrapper.state().selectionnr).toBe(2);

            global.fetch.mockClear();
            done();
        });
    });

    it('test form submit', done => {
        global.fetch = prepareFetchApi([{}, {}]);

        const wrapper = shallow(<HomePage/>);

        const fakeEvent = {preventDefault: () => console.log('preventDefault')};
        wrapper.find(".searchform").simulate('submit', fakeEvent);

        expect(wrapper.state().selectionnr).toBe(0);

        process.nextTick(() => {
            // state to be set correctly with response
            expect(wrapper.state().selectionnr).toBe(2);

            global.fetch.mockClear();
            done();
        });
    });

    it('test no backend connection behaviour', done => {
        // this test assumes a console.log within every connection fail
        global.fetch = prepareFailingFetchApi();

        let count = 0;
        global.console.log = jest.fn((m) => {
            count++;
        });

        const wrapper = shallow(<HomePage/>);

        process.nextTick(() => {
            // state to be set correctly with response
            expect(global.fetch).toBeCalledTimes(2);

            global.fetch.mockClear();
            done();
        });
    });
});