Fixtures

Fixtures are an important part of testing. Their main purpose is to set up the environment in a fixed/known state so that your tests are repeatable and run in an expected way. Yii provides a fixture framework that allows you to define your fixtures precisely and use them easily both when running your tests with Codeception and independently.

A key concept in the Yii fixture framework is the so-called fixture object. A fixture object represents a particular aspect of a test environment and is an instance of yii\test\Fixture or its child class. For example, you may use UserFixture to make sure the user DB table contains a fixed set of data. You load one or multiple fixture objects before running a test and unload them when finishing.

A fixture may depend on other fixtures, specified via its yii\test\Fixture::$depends property. When a fixture is being loaded, the fixtures it depends on will be automatically loaded BEFORE the fixture; and when the fixture is being unloaded, the dependent fixtures will be unloaded AFTER the fixture.

Defining a Fixture

To define a fixture, create a new class by extending yii\test\Fixture or yii\test\ActiveFixture. The former is best suited for general purpose fixtures, while the latter has enhanced features specifically designed to work with database and ActiveRecord.

The following code defines a fixture about the User ActiveRecord and the corresponding user table.

<?php
namespace app\tests\fixtures;

use yii\test\ActiveFixture;

class UserFixture extends ActiveFixture
{
    public $modelClass = 'app\models\User';
}

Tip: Each ActiveFixture is about preparing a DB table for testing purpose. You may specify the table by setting either the yii\test\ActiveFixture::$tableName property or the yii\test\ActiveFixture::$modelClass property. If the latter, the table name will be taken from the ActiveRecord class specified by modelClass.

Note: yii\test\ActiveFixture is only suited for SQL databases. For NoSQL databases, Yii provides the following ActiveFixture classes:

The fixture data for an ActiveFixture fixture is usually provided in a file located at FixturePath/data/TableName.php, where FixturePath stands for the directory containing the fixture class file, and TableName is the name of the table associated with the fixture. In the example above, the file should be @app/tests/fixtures/data/user.php. The data file should return an array of data rows to be inserted into the user table. For example,

<?php
return [
    'user1' => [
        'username' => 'lmayert',
        'email' => 'strosin.vernice@jerde.com',
        'auth_key' => 'K3nF70it7tzNsHddEiq0BZ0i-OU8S3xV',
        'password' => '$2y$13$WSyE5hHsG1rWN2jV8LRHzubilrCLI5Ev/iK0r3jRuwQEs2ldRu.a2',
    ],
    'user2' => [
        'username' => 'napoleon69',
        'email' => 'aileen.barton@heaneyschumm.com',
        'auth_key' => 'dZlXsVnIDgIzFgX4EduAqkEPuphhOh9q',
        'password' => '$2y$13$kkgpvJ8lnjKo8RuoR30ay.RjDf15bMcHIF7Vz1zz/6viYG5xJExU6',
    ],
];

You may give an alias to a row so that later in your test, you may refer to the row via the alias. In the above example, the two rows are aliased as user1 and user2, respectively.

Also, you do not need to specify the data for auto-incremental columns. Yii will automatically fill the actual values into the rows when the fixture is being loaded.

Tip: You may customize the location of the data file by setting the yii\test\ActiveFixture::$dataFile property. You may also override yii\test\ActiveFixture::getData() to provide the data.

As we described earlier, a fixture may depend on other fixtures. For example, a UserProfileFixture may need to depends on UserFixture because the user profile table contains a foreign key pointing to the user table. The dependency is specified via the yii\test\Fixture::$depends property, like the following,

namespace app\tests\fixtures;

use yii\test\ActiveFixture;

class UserProfileFixture extends ActiveFixture
{
    public $modelClass = 'app\models\UserProfile';
    public $depends = ['app\tests\fixtures\UserFixture'];
}

The dependency also ensures, that the fixtures are loaded and unloaded in a well defined order. In the above example UserFixture will always be loaded before UserProfileFixture to ensure all foreign key references exist and will be unloaded after UserProfileFixture has been unloaded for the same reason.

In the above, we have shown how to define a fixture about a DB table. To define a fixture not related with DB (e.g. a fixture about certain files and directories), you may extend from the more general base class yii\test\Fixture and override the load() and unload() methods.

Using Fixtures

If you are using Codeception to test your code, you can use built-in support for loading and accessing fixtures.

If you are using other testing frameworks, you may use yii\test\FixtureTrait in your test cases to achieve the same goal.

In the following we will describe how to write a UserProfile unit test class using Codeception.

In your unit test class extending \Codeception\Test\Unit either declare fixtures you want to use in the _fixtures() method or use haveFixtures() method of an actor directly. For example,

namespace app\tests\unit\models;


use app\tests\fixtures\UserProfileFixture;

class UserProfileTest extends \Codeception\Test\Unit
{   
    public function _fixtures()
    {
        return [
            'profiles' => [
                'class' => UserProfileFixture::className(),
                // fixture data located in tests/_data/user.php
                'dataFile' => codecept_data_dir() . 'user.php'
            ],
        ];
    }

    // ...test methods...
}

The fixtures listed in the _fixtures() method will be automatically loaded before a test is executed. And as we described before, when a fixture is being loaded, all its dependent fixtures will be automatically loaded first. In the above example, because UserProfileFixture depends on UserFixture, when running any test method in the test class, two fixtures will be loaded sequentially: UserFixture and UserProfileFixture.

When specifying fixtures for both _fixtures() and haveFixtures(), you may use either a class name or a configuration array to refer to a fixture. The configuration array will let you customize the fixture properties when the fixture is loaded.

You may also assign an alias to a fixture. In the above example, the UserProfileFixture is aliased as profiles. In the test methods, you may then access a fixture object using its alias in grabFixture() method. For example,

$profile = $I->grabFixture('profiles', 'user1');` will return the `UserProfileFixture` object.

Because `UserProfileFixture` extends from `ActiveFixture`, you may further use the following syntax to access
the data provided by the fixture:

```php
// returns the UserProfile model corresponding to the data row aliased as 'user1'
$profile = $I->grabFixture('profiles', 'user1');
// traverse data in the fixture
foreach ($I->grabFixture('profiles') as $profile) ...

Organizing Fixture Classes and Data Files

By default, fixture classes look for the corresponding data files under the data folder which is a sub-folder of the folder containing the fixture class files. You can follow this convention when working with simple projects. For big projects, chances are that you often need to switch different data files for the same fixture class for different tests. We thus recommend that you organize the data files in a hierarchical way that is similar to your class namespaces. For example,

# under folder tests\unit\fixtures

data\
    components\
        fixture_data_file1.php
        fixture_data_file2.php
        ...
        fixture_data_fileN.php
    models\
        fixture_data_file1.php
        fixture_data_file2.php
        ...
        fixture_data_fileN.php
# and so on

In this way you will avoid collision of fixture data files between tests and use them as you need.

Note: In the example above fixture files are named only for example purpose. In real life you should name them according to which fixture class your fixture classes are extending from. For example, if you are extending from yii\test\ActiveFixture for DB fixtures, you should use DB table names as the fixture data file names; If you are extending from yii\mongodb\ActiveFixture for MongoDB fixtures, you should use collection names as the file names.

The similar hierarchy can be used to organize fixture class files. Instead of using data as the root directory, you may want to use fixtures as the root directory to avoid conflict with the data files.

Managing fixtures with yii fixture

Yii supports fixtures via the yii fixture command line tool. This tool supports:

  • Loading fixtures to different storage such as: RDBMS, NoSQL, etc;
  • Unloading fixtures in different ways (usually it is clearing storage);
  • Auto-generating fixtures and populating it with random data.

Fixtures data format

Lets assume we have fixtures data to load:

#users.php file under fixtures data path, by default @tests\unit\fixtures\data

return [
    [
        'name' => 'Chase',
        'login' => 'lmayert',
        'email' => 'strosin.vernice@jerde.com',
        'auth_key' => 'K3nF70it7tzNsHddEiq0BZ0i-OU8S3xV',
        'password' => '$2y$13$WSyE5hHsG1rWN2jV8LRHzubilrCLI5Ev/iK0r3jRuwQEs2ldRu.a2',
    ],
    [
        'name' => 'Celestine',
        'login' => 'napoleon69',
        'email' => 'aileen.barton@heaneyschumm.com',
        'auth_key' => 'dZlXsVnIDgIzFgX4EduAqkEPuphhOh9q',
        'password' => '$2y$13$kkgpvJ8lnjKo8RuoR30ay.RjDf15bMcHIF7Vz1zz/6viYG5xJExU6',
    ],
];

If we are using fixture that loads data into database then these rows will be applied to users table. If we are using nosql fixtures, for example mongodb fixture, then this data will be applied to users mongodb collection. In order to learn about implementing various loading strategies and more, refer to official documentation. Above fixture example was auto-generated by yii2-faker extension, read more about it in these section. Fixture classes name should not be plural.

Loading fixtures

Fixture classes should be suffixed by Fixture class. By default fixtures will be searched under tests\unit\fixtures namespace, you can change this behavior with config or command options. You can exclude some fixtures due load or unload by specifying - before its name like -User.

To load fixture, run the following command:

Note: Prior to loading data unload sequence is executed. Usually that results in cleaning up all the existing data inserted by previous fixture executions.

yii fixture/load <fixture_name>

The required fixture_name parameter specifies a fixture name which data will be loaded. You can load several fixtures at once. Below are correct formats of this command:

// load `User` fixture
yii fixture/load User

// same as above, because default action of "fixture" command is "load"
yii fixture User

// load several fixtures
yii fixture "User, UserProfile"

// load all fixtures
yii fixture/load "*"

// same as above
yii fixture "*"

// load all fixtures except ones
yii fixture "*, -DoNotLoadThisOne"

// load fixtures, but search them in different namespace. By default namespace is: tests\unit\fixtures.
yii fixture User --namespace='alias\my\custom\namespace'

// load global fixture `some\name\space\CustomFixture` before other fixtures will be loaded.
// By default this option is set to `InitDbFixture` to disable/enable integrity checks. You can specify several
// global fixtures separated by comma.
yii fixture User --globalFixtures='some\name\space\Custom'

Unloading fixtures

To unload fixture, run the following command:

// unload Users fixture, by default it will clear fixture storage (for example "users" table, or "users" collection if this is mongodb fixture).
yii fixture/unload User

// Unload several fixtures
yii fixture/unload "User, UserProfile"

// unload all fixtures
yii fixture/unload "*"

// unload all fixtures except ones
yii fixture/unload "*, -DoNotUnloadThisOne"

Same command options like: namespace, globalFixtures also can be applied to this command.

Configure Command Globally

While command line options allow us to configure the migration command on-the-fly, sometimes we may want to configure the command once for all. For example you can configure different migration path as follows:

'controllerMap' => [
    'fixture' => [
        'class' => 'yii\console\controllers\FixtureController',
        'namespace' => 'myalias\some\custom\namespace',
        'globalFixtures' => [
            'some\name\space\Foo',
            'other\name\space\Bar'
        ],
    ],
]

Auto-generating fixtures

Yii also can auto-generate fixtures for you based on some template. You can generate your fixtures with different data on different languages and formats. This feature is done by Faker library and yii2-faker extension. See extension guide for more docs.

Summary

In the above, we have described how to define and use fixtures. Below we summarize the typical workflow of running unit tests related with DB:

  1. Use yii migrate tool to upgrade your test database to the latest version;
  2. Run a test case:
    • Load fixtures: clean up the relevant DB tables and populate them with fixture data;
    • Perform the actual test;
    • Unload fixtures.
  3. Repeat Step 2 until all tests finish.