gitlab-org--gitlab-foss/spec/frontend/behaviors/autosize_spec.js

38 lines
1.5 KiB
JavaScript

import '~/behaviors/autosize';
jest.mock('~/helpers/startup_css_helper', () => {
return {
waitForCSSLoaded: jest.fn().mockImplementation((cb) => {
// This is a hack:
// autosize.js will execute and modify the DOM
// whenever waitForCSSLoaded calls its callback function.
// This setTimeout is here because everything within setTimeout will be queued
// as async code until the current call stack is executed.
// If we would not do this, the mock for waitForCSSLoaded would call its callback
// before the fixture in the beforeEach is set and the Test would fail.
// more on this here: https://johnresig.com/blog/how-javascript-timers-work/
setTimeout(() => {
cb.apply();
}, 0);
}),
};
});
describe('Autosize behavior', () => {
beforeEach(() => {
setFixtures('<textarea class="js-autosize"></textarea>');
});
it('is applied to the textarea', () => {
// This is the second part of the Hack:
// Because we are forcing the mock for WaitForCSSLoaded and the very end of our callstack
// to call its callback. This querySelector needs to go to the very end of our callstack
// as well, if we would not have this setTimeout Function here, the querySelector
// would run before the mockImplementation called its callBack Function
// the DOM Manipulation didn't happen yet and the test would fail.
setTimeout(() => {
const textarea = document.querySelector('textarea');
expect(textarea.classList).toContain('js-autosize-initialized');
}, 0);
});
});