Unit test helpers mocking an I18n environment

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Components etc. in Ember make regular use of translated contents, either calculated in code or accessed in templates. Conceptually, these units expect a translation service to be made available to them as part of their usage contract to be actually testable.
A fully integrated and configured translation service such as ember-i18n using real translations can't be considered a unit test, it's more of an integration test.
This library gives you helper functions to provide a mocked translation service for your tests, making them both more readable and less brittle to changing translations.


ember install ember-i18n-test-helpers
then you can do:
import { mockI18n } from 'ember-i18n-test-helpers';

moduleForComponent('time-block', {
	unit: true,

	beforeEach() {
				global: {
					now: 'NOW',
					ago: params => 'AGO_' + params.seconds
			.with('yes', 'YES');

// ...

test('is displaying difference with ago if difference is -10', function (assert) {

	var component = this.subject();
	Ember.run(component, 'set', 'difference', -10);

	assert.equal(component.get('humanizedDifference'), 'AGO_10');

test('is displaying now if difference is 0', function (assert) {

	var component = this.subject();
	Ember.run(component, 'set', 'difference', 0);

	assert.equal(component.get('humanizedDifference'), 'NOW');

Unless you set a default value (see below), the translation helpers will throw an error (thus usually failing the test), if the translation for a key was not specified beforehand.

Default Value

If you do not want to specify the full set of translations your component needs and don't care for the exact strings it generates, you can set a default value for the t helpers:
beforeEach() {
		.with('now', 'jetzt')
		.with('later', 'nachher'); // you can still set specific values, taking precedence.

You can also unset the default if you don't need it later with .withoutDefault().


Currently, two syntaxes are supported. The first maps keys directly to values:
mockI18n().with('global.now', 'NOW');

assert.equals(t('global.now'), 'NOW');

Alternatively, you can also just throw in a whole object that is parsed recursively:
  .with({ global: {now: 'NOW'} });

assert.equals(t('global.now'), 'NOW');

More Examples

The test cases in the dummy application testing a component displaying time differences use all available features.


  • git clone this repository
  • npm install
  • bower install
  • ember serve
  • Visit your app at http://localhost:4200.

Running Tests

  • ember test
  • ember test --server


  • ember build

For more information on using ember-cli, visit http://www.ember-cli.com/.