Ember.js Advanced Testing: Handling Services and Adapters

Ember.js provides a robust testing framework that allows developers to write unit tests, integration tests, and acceptance tests for their applications. In this article, we will explore how to use Ember.js to handle testing with services and adapters, and discuss some advanced testing techniques.

Testing Services

Services in Ember.js are singleton objects that provide a way to share data and functionality across the application. To test a service, you need to inject it into your test module and then use it in your test.

// tests/unit/services/my-service-test.js
import { module, test } from 'qunit';
import { setupTest } from 'ember-qunit';

module('Unit | Service | my-service', function(hooks) {
  setupTest(hooks);

  test('it exists', function(assert) {
    const service = this.owner.lookup('service:my-service');
    assert.ok(service);
  });
});

Testing Service Methods

To test a service method, you can call the method on the service instance and then assert that the expected behavior occurred.

// tests/unit/services/my-service-test.js
import { module, test } from 'qunit';
import { setupTest } from 'ember-qunit';

module('Unit | Service | my-service', function(hooks) {
  setupTest(hooks);

  test('it calls the API', function(assert) {
    const service = this.owner.lookup('service:my-service');
    const apiSpy = sinon.spy(service, 'callApi');

    service.doSomething();

    assert.ok(apiSpy.calledOnce);
  });
});

Testing Adapters

Adapters in Ember.js are used to define how data is retrieved and updated. To test an adapter, you need to inject it into your test module and then use it in your test.

// tests/unit/adapters/my-adapter-test.js
import { module, test } from 'qunit';
import { setupTest } from 'ember-qunit';

module('Unit | Adapter | my-adapter', function(hooks) {
  setupTest(hooks);

  test('it exists', function(assert) {
    const adapter = this.owner.lookup('adapter:my-adapter');
    assert.ok(adapter);
  });
});

Testing Adapter Methods

To test an adapter method, you can call the method on the adapter instance and then assert that the expected behavior occurred.

// tests/unit/adapters/my-adapter-test.js
import { module, test } from 'qunit';
import { setupTest } from 'ember-qunit';

module('Unit | Adapter | my-adapter', function(hooks) {
  setupTest(hooks);

  test('it calls the API', function(assert) {
    const adapter = this.owner.lookup('adapter:my-adapter');
    const apiSpy = sinon.spy(adapter, 'callApi');

    adapter.findRecord();

    assert.ok(apiSpy.calledOnce);
  });
});

Advanced Testing Techniques

Ember.js provides several advanced testing techniques that can be used to test complex scenarios.

Testing Asynchronous Code

To test asynchronous code, you can use the `wait` helper provided by Ember.js.

// tests/unit/services/my-service-test.js
import { module, test } from 'qunit';
import { setupTest } from 'ember-qunit';

module('Unit | Service | my-service', function(hooks) {
  setupTest(hooks);

  test('it calls the API asynchronously', function(assert) {
    const service = this.owner.lookup('service:my-service');
    const apiSpy = sinon.spy(service, 'callApi');

    service.doSomethingAsync();

    return wait().then(() => {
      assert.ok(apiSpy.calledOnce);
    });
  });
});

Testing Ember Components

To test Ember components, you can use the `render` helper provided by Ember.js.

// tests/integration/components/my-component-test.js
import { module, test } from 'qunit';
import { setupRenderingTest } from 'ember-qunit';
import hbs from 'htmlbars-inline-precompile';

module('Integration | Component | my-component', function(hooks) {
  setupRenderingTest(hooks);

  test('it renders', function(assert) {
    this.render(hbs`{{my-component}}`);

    assert.equal(this.$('.my-component').length, 1);
  });
});

Conclusion

In this article, we explored how to use Ember.js to handle testing with services and adapters. We also discussed some advanced testing techniques, including testing asynchronous code and Ember components. By using these techniques, you can write robust tests for your Ember.js application.

Frequently Asked Questions

What is the purpose of the `setupTest` function in Ember.js testing?

The `setupTest` function is used to set up the test environment for Ember.js tests. It injects the necessary dependencies and sets up the test context.

How do I test a service in Ember.js?

To test a service in Ember.js, you need to inject it into your test module and then use it in your test. You can use the `this.owner.lookup` method to inject the service.

How do I test an adapter in Ember.js?

To test an adapter in Ember.js, you need to inject it into your test module and then use it in your test. You can use the `this.owner.lookup` method to inject the adapter.

What is the `wait` helper in Ember.js testing?

The `wait` helper is used to test asynchronous code in Ember.js. It allows you to wait for a promise to resolve before continuing with the test.

How do I test an Ember component?

To test an Ember component, you can use the `render` helper provided by Ember.js. This helper allows you to render the component and then assert that it renders correctly.