Adding Database Tests to Existing PHPUnit Test Cases

So, now you might be wondering how can I use this class to add data-centric tests to my existing test case. I am going to use the BankAccount example that exists in PHPUnit to show you. Below you can find the existing bank account test case (without comments.)

I would like to add a test to see if a bank account is created in the database when the bank account's constructor is called. This is the same test I showed you in my first example of the database extension. However, I do not want to add the overhead of creating and seeding the database for my existing tests that obviously doesn't need them. I should tell you right away that I would actually prefer in these cases to just create a new test case to handle just the data-centric tests. However, one thing using composition will assist greatly with is if you want to test database code that should throw exceptions as well as perform data operations. I am sure there are many other valid uses that I haven't even thought of as well.

First thing I need to do is add an instance of PHPUnit_Extensions_Database_DefaultTester to the test case. To create a tester instance I will need to have a pdo connection. For this example I am going to use a database I created on my local machine in mysql.

I will now need to specify the different events that will occur on startUp and tearDown of the new test and the data that will be used. To do this I am going to add a few calls to the tester in my getDatabaseTester() method. The first method, setSetUpOperation(), will tell the tester which operation I would like to perform on the database at the start of each test. Likewise, the second method setTearDownOperation() will tell the tester which operation to perform on the database at the end of each test. Both of these methods will accept an object implementing PHPUnit_Extensions_Database_Operation_IDatabaseOperation. The most common one you will probably want to use is the 'clean insert' operation. This operation will perform a truncate on each table in your data set and then insert all rows in the dataset. I am going to use a factory class to generate the operation. If you want to view all of the current operations available I recommend browsing the following src directory: http://www.phpunit.de/browser/phpunit/branches/3.2/PHPUnit/Extensions/Database/Operation. The final method we will need to call is setDataSet(). This will accept any of the data set objects. I am just going to use a flat xml data set with a few rows.

So with these new changes our getDatabaseTester() method will look like this:

You will notice that I used an operation called NONE() on teardown. This, as you may have guessed, is a NULL operation. It does absolutely nothing which in this case is perfectly alright since we are truncating at the the beginning of each test.

Now I am ready to add my new test method. In this test I am going to call my getDatabaseTester(). I will the call the onSetUp() method of the tester. This will perform the setup operation that we specified previously. Then I will create a new bank account, retrieve a dataset from the connection I created in getDatabaseTester() (utilizing the getConnection() method,) and compare the results using the assertDataSetsEqual() static method of the Database TestCase class. Finally I will clean up my mess (which in this case means nothing) using the onTearDown() method of the tester object.

You will notice that I have access to the two asserts of the database test case. They are static, public methods and can be accessed from anywhere.

That's all there is to it. Now you can just go nuts adding new database tests or plain old php tests only incurring the database overhead when needed.