Introducing Fixtures for Lithium

When you write tests for your classes (and you should), you may run into the problem that you create large arrays of test data in your code. Consider the following example:

$expected = array(
    'post1' => array(
        'title' => 'My First Post',
        'content' => 'First Content...'
    ),
    'post2' => array(
        'title' => 'My Second Post',
        'content' => 'Also some foobar text'
    ),
    'post3' => array(
        'title' => 'My Third Post',
        'content' => 'I like to write some foobar foo too'
    )
);

$this->assertEqual($expected[0], Post::first());
/* more tests down here */

This creates a nested array of test data where each inner array mocks a post stored in the database. If we have to do this more than once (maybe in an other test we insert this data into the database to test validations), we may put the snippet in the setUp() method. A better approach would be to move this code in fixture files. The li3_fixtures plugin tries to help you with that and provides a simple and convenient approach to integrate fixtures in your tests.

Before we can use the plugin, we need to install it first. li3_fixtures doesn’t have any dependencies, so this is straightforward. Note that for now you need a rad-dev.org-account to clone the repository.

$ cd /path/to/app/libraries
$ git clone [email protected]:li3_fixtures.git
$ mkdir /path/to/app/tests/fixtures

Now we need to tell our app to use the plugin, so fire up your editor and modify your app/config/bootstrap/libraries.php.

Libraries::add('li3_fixtures');

After that, we can create a sample fixture file in app/tests/fixtures/posts.json. Currently only json-files are supported, but xml-support is planned.

{
    "post1": {
        "title": "My First Post",
        "body": "First Content..."
    },
    "post2": {
        "title": "My Second Post",
        "body": "Also some foobar text"
    },
    {
        "title": "My Third Post",
        "body": "I like to write some foobar foo too"
    }
}

Now that we have our fixture file in place, lets see how the $this->assertEqual() looks like (don’t forget to use the li3_fixtures plugin with use li3_fixtures\test\Fixture;):

$fixtures = Fixture::load('Post');
$this->assertEqual($fixtures->first(), Post::first());

By convention, your $model in Fixture::load($model)well be lowercased and pluralized by the Inflector (so ‘Post’ loads ‘posts.json’). The load-method also takes an optional argument where you can override various default settings like the extension or location of the fixture-file.

As you can see, your test code is significantly smaller and easier to read. You may also notice the first()-method here. li3_fixtures makes use of the built in lithium\util\Collection class, which provides a powerful set of collection management methods like first(), next() or prev(). Check out the lithium\util\Collection documentation for more info on that.

The project can be found at rad-dev.org/li3_fixtures and is maintained by me, so if you have any comments or questions, feel free to ask comment here or contact me directly.