ember-native-dom-helpers

Test helpers for integration tests that mimic the behaviour of the acceptance test helpers provided by Ember.

Use this addon as a way to start the gradual migration towards the future "testing unification" RFC which proposes only native DOM.

See the Grand Testing Unification RFC

Status: (Pre) 1.0, although we have a good idea what the needs are for test helpers, we are working though a few points on what changes are needed when using only standard DOM APIs (i.e. without jQuery).

Usage

Integration tests

import { click, fillIn, find, findAll, keyEvent, triggerEvent } from 'ember-native-dom-helpers';

moduleForComponent('my-component', 'Integration | Component | my-component', {
  integration: true
});


test('I can interact with my component', async function(assert) {
  this.render(hbs```
    {{my-component}}
  ```);

  await fillIn('.some-input');
  await click('.main-button');
  await keyEvent('.other-input', 'keyup', 40); // down arrow
  await triggerEvent('.some-drop-area', 'mouseenter');

  assert.ok(find('.result-of-event-happened'));
  assert.equal(findAll('.result-list-item').length, 3);
})

Acceptance tests

You can use the exact same helpers for your acceptance tests. All interaction helpers like click, fillIn et al. return a promise that that fullfils when "the world has settled" (that is, there is no pending requests or promises and the runloop has be drained), which is what the andThen acceptance helper used to do. However now this helper can be replace by the async/await syntax in ES2017 yielding easier to read tests:

import { visit, click, find, fillIn } from 'ember-native-dom-helpers';

moduleForAcceptance('Acceptance | Sign up');

test('Usage awaiting the world to settle', async function(assert) {
  await visit('/sign-up');

  await fillIn('.first-name', 'Chuck');
  await fillIn('.last-name', 'Berry');
  await click('.submit-btn');

  assert.ok(find('.welcome-msg'), 'There is a welcome banner');
  assert.equal(find('.welcome-msg-name'), 'Chuck');
});

Advantages compared with `this.$(selector).click()`

The main advantages are:

Fire native events: In Ember, when adding events with the onclick={{action "foo"}} syntax, dispatching jQuery events leads to the action being called twice. Besides there is subtle differences between jQuery and Native events and can bite you. Firing native events fixes that problem but they are very verbose and there is browsers incompatibilities. This addon makes firing native events a no-brainer.
Runloop aware: This helpers automatically spawn a runloop, so you don't need to wrap every interaction with Ember.run(() => /* interact with element */ );.
wait by default: All the helpers return the wait() promise, making possible wait for asynchronous side-effects with async/await. (Note that for using async/await in browsers without native support you must install ember-maybe-import-regenerator)
```
test('some test', async function(assert) {
  this.render(hbs```{{my-component}}```);

  await click('.my-button');

  assert.ok('something happened');
});
```
More real behaviour: When a clicks on an element click is not the only event fired. In a real click the sequence of events is mousedown, focus, mouseup, click. When a user fills in an input the sequence of events is focus, <mutate-value>, input and change. The helpers provided by this addon fire those events in the right order simulating more closely how a real user would interact with the page.

Standard DOM elements returned using a `find`/`findAll` helpers

The find helper uses document.querySelector and will return a single HTMLElement or null.
The findAll helper uses document.querySelectorAll and returns an Array with zero or more elements.
Both find and findAll helpers query the DOM within #ember-testing.
To use a different value from your config/environment.js settings, add to tests/test-helper.js…

import { settings } from 'ember-native-dom-helpers';
import config from '../config/environment';
const { APP: { rootElement } } = config;

settings.rootElement = rootElement || settings.rootElement;

What if I prefer jQuery collections over native DOM

Fear not. If you prefer to use jQuery, just wrap the result and do your thing:

assert.equal($(find('.my-class')).attr('aria-owns'), '#id123')

Testing an unsettled world

There is one new helper in this addon that enables some testing patters that weren't previously easy to perform using traditional methods.

Since the andThen helper waits for the app to settle (no pending requests or promises) and in integration tests every interaction is wrapped in Ember.run, there was no easy way of testing transient state like loading substates or the state of a components while some promise is pending without a awkward setup of timeouts.

Now however thanks to explicit usage of promises and the waitUntil helper you can perform assertions on unsettled states:

import { visit, click, find, fillIn, waitUntil, currentURL } from 'ember-native-dom-helpers';

moduleForAcceptance('Acceptance | Sign up');

test('Usage awaiting the world to settle', async function(assert) {
  await visit('/login');

  await fillIn('.email', '007@gov.uk');
  await fillIn('.password', 'goldeneye');
  let promise = click('.submit-btn');

  // We wait until the loading substate, that takes 200ms to appear, is displayed
  await waitUntil(() => find('.susbstate-spinner'));
  assert.equal(find('.loading-substate-header').textContent.trim(), 'Loading mission. Please wait, Mr. Bond');

  await promise; // now we wait until the dashboard is fully loaded
  assert.equal(currentURL(), '/dashboard');
  assert.equal(find('.section-header').textContent, 'Main dashboard');
});

I WANT IT NOW, IS THERE A SHORTCUT?

Yes, there is an codemod that will help you transform your test suite to this new style "automatically". Check https://github.com/simonihmig/ember-native-dom-helpers-codemod.

The codemod can't make a perfect convertion, but it will do most of the work for you.

Helpers

click(selectorOrHTMLElement, eventOptions)
tap(selectorOrHTMLElement, eventOptions)
fillIn(selectorOrHTMLElement, text)
find(selector, contextHTMLElement) (query for an element in test DOM, #ember-testing)
findAll(selector, context) (query for elements in test DOM, #ember-testing)
findWithAssert(selector, contextHTMLElement) (same as find, but raises an Error if no result)
keyEvent(selectorOrHTMLElement, type, keyCode, modifiers) (type being keydown, keyup or keypress, modifiers being object with { ctrlKey: false, altKey: false, shiftKey: false, metaKey: false })
triggerEvent(selectorOrHTMLElement, type, options)
focus(selectorOrHTMLElement)
blur(selectorOrHTMLElement)
scrollTo(selectorOrHTMLElement, x, y)
selectFiles(selectorOrHTMLElement, files = []) (selects the file(s)/Blob(s) to the given input[type=file]. Example
visit(url) (only available in acceptance. Raises an error in integration)
waitUntil(function, options) (Polls the page until the given callback returns a truthy value, or timesout after 1s)
currentURL() Identical to the one provided by Ember.
currentPath() Identical to the one provided by Ember.
currentRouteName() Identical to the one provided by Ember.

Notes of `tap`

In order for tap to work, your browser has to support touch events. Desktop Chrome and Firefox have touch events disabled unless the device emulation mode is on. In order to enable touch events in your CI, you need to configure testem like the testem.js file on this repo.

ro0gr/ember-native-dom-helpers