Unit Testing your Models

Writing unit tests for your Propel or Doctrine model is much more easier as of symfony 1.1. In this tutorial, you will learn some great tips and best practices to write better tests for your models.

Database Configuration

To test a Propel model class, you need a database. You already have the one you use for your development, but it is always a good habit to create a dedicated one for your tests.

As all tests are run under the test environment, we just need to edit the config/databases.yml configuration file and override the default settings for the test environment:

      dsn:  mysql:dbname=myproject_test;host=localhost
  # dev configuration
    class: sfPropelDatabase
      dsn:        mysql:dbname=myproject;host=localhost
      username:   someuser
      password:   somepa$$word
      encoding:   utf8
      persistent: true
      pooling:    true
      classname:  PropelPDO

In this case, we have only changed the database name, but you can also change the database engine and use SQLite for example.

Now that we have configured the database, we can create the tables by using the propel:insert-sql task:

$ php symfony propel:insert-sql --env=test

This is new in symfony 1.2. With symfony 1.1, you will have to manually create the tables by using the generate SQL statements found in data/sql:

$ mysql myproject_test < data/sql/*.sql

Test Data

Now that we have a dedicated database for our tests, we need a way to load some test data (fixtures) each time we launch the unit tests. That's because we want to put the database in the same state each time we run our tests.

It is pretty easy thanks to the sfData class:

$loader = new sfPropelData();

The loadData() method takes a directory or a file as its first argument. A common fixtures directory looks like this:


Notice the numbers prefixing all filenames. This is a simple way to control the order of data loading. Later in the project, if we need to insert some fixture file, it will be easy as we have some free numbers between existing ones:


Astute readers will have spotted that we have put our fixtures in the test/ directory, whereas the symfony book advocates to put them in the data/ directory. This is really a matter of taste, but I like to organize my fixtures in these two directories because fixtures can be categorized in two different groups:

  • data/fixtures: contains all initial data needed to make the application actually work
  • test/fixtures: contains all data needed by the tests (unit and functional)

This simple scheme works fine when you have a small set of test data, but when your model grows, you start having a lot more fixtures, and the time it takes to load them in the database can become significant. So, we need a way to only load a sub-set of our test data. One way to do it is to sub-categorize your test data by creating a sub-directory per main feature:


Now, instead of loading the main fixtures directory, we can just load one of the sub-directories, depending on the model class you want to test. But most of the time, you also need to load some shared data, like users:


To ease this use case, the symfony 1.2 loadData() method is able to take an array of directories and/or files:

// load users and all the CMS data
$loader = new sfPropelData();

This will load the 10_users.yml fixture file and then all the fixtures found in the 10_cms directory.

Writing Unit Tests

Now that we have a dedicated database and a way to put our database in a known state, let's create some unit tests for the Article model.

As of symfony 1.1, the bootstrapping of a Propel unit test has been simplified a lot thanks to the new configuration classes:

// test/unit/model/ArticlePeerTest.php
$configuration = ProjectConfiguration::getApplicationConfiguration('frontend', 'test', true);
new sfDatabaseManager($configuration);
$loader = new sfPropelData();
$t = new lime_test(1, new lime_output_color());
$article = ArticlePeer::retrieveBySlug('the-best-framework-ever');
$t->is($article->getTitle(), 'The Best Framework Ever', '->retrieveBySlug() returns the article that matches the given slug');

The script is pretty self-explanatory:

  • As for every unit test, we include the bootstrapping file.

  • We create a configuration object for the test environment and we enable debugging:

    $configuration = ProjectConfiguration::getApplicationConfiguration('frontend', 'test', true);

    This will also initialize the autoloading of all Propel classes.

  • We create a database manager. It initializes the Propel connection by loading the databases.yml configuration file:

    new sfDatabaseManager($configuration);
  • We load our test data by using sfPropelData:

    $loader = new sfPropelData();
  • Now that everything is in place, we can start testing our model object.

If you are not used to write unit tests, it can be intimidating at first.

Here are some tips I use all the time to know what I need to test:

  • Test one method of a class at a time
  • Test that for a given input, the output of the method is what you expect
  • Read the method code and test all the business rules you might have
  • Never test obvious things or things that are done by another method

My test files are always structured with the same pattern:

// output a message with the method you test (-> for instance methods, and :: for class methods)
// test 1 thing at a time that can be expressed as a simple sentence
// The sentence always begin with the method name
// then a verb to express what must be done, how it must behave, ...
$t->is($object->methodName(), 1, '->methodName() returns 1 if you pass no argument');

Code coverage

When you write tests, it is easy to forget to test a condition in a complex code.

As of symfony 1.2, we provide a little handy task to test the code coverage, test:coverage.

So, after my tests are written for a given class, I always launch the test:coverage task to be sure I have tested everything:

$ php symfony test:coverage test/unit/model/ArticleTest.php lib/model/Article.php

The first argument is a test file or a test directory. The second one is the file or directory for which you want to know the code coverage.

If you want to know which lines are not covered, simply add the --detailed option:

$ php symfony test:coverage --detailed test/unit/model/ArticleTest.php lib/model/Article.php

It has never been easier to unit test your model classes. Give it a try!


Indeed, very handy.
Thank you :)
I really like the test:coverage task!

Is there a way to test the coverage of a directory or in other words of all files in a directory? Testing each file by hand can be a boring task..
@Matthias: sure, just pass a directory instead of a file.
And how can I load fixtures with Doctrine, since there is no sfDoctrineData class?
@Joaquin Bravo:

Thanks, useful post. But I'm wondering if there is any way to change the testing framework? I'm very accustomed to PHPUnit and would prefer the tests to be written in it, for portability, independence, and legacy reasons.
The code coverage is very good. TDD was already simple in symfony, now it´s very productive.
thanks pablodip.
@gasper_k: You can use PHPUnit if you want, this is not mandatory ti use lime.
I try $loader->loadData(array(....)); but it not worked - need file or dir in param. Why?
haber scripti
@serg: It can take an array as of symfony 1.2.

This post has been also published in the cookbook.
The 1.1 version is here:


And the 1.2 version here:


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