Working with Data

Tests should not affect each other. That's a rule of thumb. When tests interact with database, they may change data inside it, which would eventually lead to data inconsistency. A test may try to insert a record that has already been inserted, or retrieve a deleted record. To avoid test failures, the database should be brought to its initial state before each test. Codeception has different methods and approaches to get your data cleaned.

This chapter summarizes all of the notices on cleaning ups from the previous chapters and suggests the best strategies of how to choose data storage backends.

When we decide to clean up a database, we should make this cleaning as fast as possible. Tests should always run fast. Rebuilding the database from scratch is not the best way, but might be the only one. In any case, you should use a special test database for testing. Do not ever run tests on development or production database!

Db

Codeception has a Db module, which takes on most of the tasks of database interaction. By default it will try to repopulate the database from a dump and clean it up after each test. This module expects a database dump in SQL format. It's already prepared for configuration in codeception.yml:

modules:
    config:
        Db:
            dsn: 'PDO DSN HERE'
            user: 'root'
            password:
            dump: tests/_data/your-dump-name.sql

After you enable this module in your test suite, it will automatically populate the database from a dump and repopulate it on each test run. These settings can be changed through the populate and cleanup options, which may be set to false.

In acceptance tests your tests are interacting with the application through a web server.This means that the test and the application will work with the same database. You should provide in the Db module the same credentials that your application uses, and then you can access the database for assertions (seeInDatabase actions) and to perform automatic cleanups.

Db module provides actions to create and verify data inside a database.

If you want to create special database record for one test, you can use haveInDatabase method of Db module.

<?php 
$I->haveInDatabase('posts', [
  'title' => 'Top 10 Testing Frameworks', 
  'body' => '1. Codeception'
]);
$I->amOnPage('/posts');
$I->see('Top 10 Testing Frameworks');

haveInDatabase inserts a row with provided values into database. All added records will be deleted in the end of a test.

If you want to check that a table record was created use seeInDatabase method:

<?php
$I->amOnPage('/posts/1');
$I->fillField('comment', 'This is nice!');
$I->click('Submit');
$I->seeInDatabase('comments', ['body' => 'This is nice!']);

Follow the module reference for other methods you can use for database testing.

There are also modules for MongoDb, Redis, Memcache which act in similar manner.

Sequence

If database cleanup takes to long for you you can follow different strategy: create new data for each test. This way the only problem you may face is duplication of data records. Sequence was created to solve this. It provides sq() function which generates unique suffixes for creating data in tests.

ORM modules

Probably your application is using ORM to work with database. In this case Codeception allows you to use methods of ORM to work with database, instead of accessing database directly. This way you can work with models and entities of a domain, and not on tables and rows.

By using ORM in functional and integration you can also improve performance of your tests. Instead of cleaning up database after each test ORM module will wrap all the database actions into transactions and rollback it in the end. This way no actual data will be written to the database. This cleanup strategy is enabled by default, you can disable it by setting cleanup: false in config of any ORM module.

ActiveRecord

Popular frameworks like Laravel, Yii, and Phalcon include ActiveRecord data layer by default. Because of this tight integration you just need to enable framework module, and use its config for database access.

Corresponding framework modules provide similar methods for ORM access:

• haveRecord
• seeRecord
• dontSeeRecord
• grabRecord

They allow to create and check data by model name and field names in model. Here is the example in Laravel

<?php
// create record and get its id
$id = $I->haveRecord('posts', ['body' => 'My first blogpost', 'user_id' => 1]);
$I->amOnPage('/posts/'.$id);
$I->see('My first blogpost', 'article');
// check record exists
$I->seeRecord('posts', ['id' => $id]);
$I->click('Delete');
// record was deleted
$I->dontSeeRecord('posts', ['id' => $id]);

In case you want to use ORM for integration testing only, you should enable framework module with only ORM part enabled:

modules:
    enabled:
        - Laravel5:
            - part: ORM

modules:
    enabled:
        - Yii2:
            - part: ORM

This way no web actions will be added to $I object.

If you want to use ORM to work with data inside acceptance tests you should also include only ORM part of a module. Please note, that inside acceptance tests web application works inside a webserver so test data can't be cleaned up by rolling back transaction. So you will need to disable cleanup and use Db module to cleanup database betweem tests. Here is a sample config:

modules:
    enabled:
        - WebDriver:
            url: http://localhost
            browser: firefox
        - Laravel5:
            cleanup: false
        - Db

DataMapper

Doctrine is also a popular ORM, unlike other it implements DataMapper pattern and is not bound to any framework. Doctrine2 module requires EntityManager instance to work with. It can be obtained from a frameworks Symfony or Zend Framework (configured with Doctrine):

modules:
    enabled:
        - Symfony
        - Doctrine2:
            depends: Symfony

modules:
    enabled:
        - ZF2
        - Doctrine2:
            depends: ZF2

If no framework is used with Doctrine you should provide connection_callback option with a valid callback to function which returns EntityManager instance.

Doctrine2 also provides methods to create and check data:

• haveInRepository
• grabFromRepository
• seeInRepository
• dontSeeInRepository

DataFactory

Preparing data for testing is a very creative nevertheless boring task. If you create a record you will need to fill in all fields of a model. It would be much easier to use Faker for this task, and which is more effective to setup data generation rules for models. Such set of rules is called factories and are provided by DataFactory module.

Once configured it can create records with ease:

<?php
// creates a new user
$user_id = $I->have('App\Model\User');
// creates 3 posts
$I->haveMultiple('App\Model\Post', 3);

Created records will be deleted at the end of a test. DataFactory works only with ORM, so require one of ORM modules to be enabled:

modules:
    enabled:
        - Yii2:
            configFile: path/to/config.php
        - DataFactory:
            depends: Yii2

modules:
    enabled:
        - Symfony
        - Doctrine2:
            depends: Symfony
        - DataFactory:
            depends: Doctrine2

DataFactory provides a powerful solution for managing data in integration/functional/acceptance tests. Read the full reference to learn how to setup this module.

Conclusion

Codeception is not leaving the developer when dealing with data. Tools for database population and cleanups are bundled within the Db module. If you use ORM you can use one of provided framework modules to operate with database through data abstraction layer, and use DataFactory module to generate new records with ease.