Testing

Introduction#

Creating and maintaining a comprehensive test suite should be a priority for each developer. Testing in Ember.js involves dealing with asynchrony, Ember Run Loop and mocking your API. It is common for Ember.js developers to struggle when writing tests. However, there are some tips which could save your time and energy.

Waiting for promises in tests in elegant way

You can make function passed to test() method async - then you can use await keyword. Your test will wait until Promises resolve and testing asynchronous code becomes easier and more readable. In the following example call that returns a Promise is changeset.validate(). Please notice also wrapping set call in Ember.run. Setting quantity has asynchronous effects (observers, computed properties) and thus we need to wrap it in Ember.run.

test('quantity validation: greater than 0', async function (assert) {
    assert.expect(3);

    const model = this.subject({
        quantity: 1
    });

    const changeset = createChangeset(model);

    await changeset.validate();

    assert.ok(!changeset.get('error.quantity'));

    Ember.run(() => {
        changeset.set('quantity', -1);
    });

    await changeset.validate();

    assert.equal(changeset.get('error.quantity.validation.length'), 1);
    assert.ok(!changeset.get('isValid'));
});