fonteva-design-guide/force-app/main/default/lwc/pfmLoader/__tests__/pfmLoaderTest.js

## Dev, Build and Test

import { createElement } from 'lwc';

import LOADER from 'c/pfmLoader';

describe('c-pfm-loader', () => {
    afterEach(() => {
        // The jsdom instance is shared across test cases in a single file so reset the DOM
        while (document.body.firstChild) {
            document.body.removeChild(document.body.firstChild);
        }
    });

    it('start loader', () => {
        const element = createElement('c-pfm-loader', {
            is: LOADER
        });

        document.body.appendChild(element);
        element.start();

        // Verify loader started
        const loader = element.shadowRoot.querySelector('.js-loader');

        return Promise.resolve().then(() => {
            expect(loader).not.toBeNull();
        });
    });

    it('start loader by prop', () => {
        const element = createElement('c-pfm-loader', {
            is: LOADER
        });

        document.body.appendChild(element);
        element.show = true;

        // Verify loader started
        const loader = element.shadowRoot.querySelector('.js-loader');

        expect(loader).not.toBeNull();
    });

    it('end loader', done => {
        const element = createElement('c-pfm-loader', {
            is: LOADER
        });

        document.body.appendChild(element);
        element.start();
        element.end();

        // The class is removed from the pfmLoader after 1 second, so delay the check
        setTimeout(()=>{
            // Verify loader ended
            const loader = element.shadowRoot.querySelector('.js-loader');

            expect(loader).toBeNull();
            done();
        }, 1500);
    });
});