Posts tagged ‘PHPUnit’

PHPUnit + XHProf = BOOM!

I ran into an issue recently while trying to run PHPUnit tests in an environment using XHProf. Google didn’t prove to be much help, so I thought I’d document the problem and solution here for posterity.

When I ran my tests, each failed with the same cryptic error and no backtrace.

Attempted to serialize unserializable builtin class PDO

The cause was the culmination of two rather unfortunate circumstances.

First, XHProf uses a global array variable to contain its configuration in its auto_prepend_file, which includes a PDO instance. Yet another reason to add to the list of reasons why global variables are bad.

Second, PHPUnit has a setting called @backupGlobals that is enabled by default. For reasons of which I’m uncertain, the library used for this applies and reverses serialization to variables in the global state for the purpose of creating a snapshot of it.

The method used for detecting serializability in this library unfortunately doesn’t presently detect that PDO can’t be serialized when an instance of it is contained within a global array variable. As a result, when PHPUnit attempts to snapshot the global state after a test has run and it encounters the PDO instance from the XHProf configuration, the error above is the result.

There appears to be a pull request with changes to this serializability detection, though I can’t speak to whether it would improve it or cover the use case causing this problem. I’ve filed a related issue against the appropriate repo. Until it’s addressed, I’d recommend either disabling @backupGlobals in your phpunit.xml file or disabling XHProf when running PHPUnit tests.

Hope this helps someone else. Thanks for reading!

Process Isolation in PHPUnit

I was recently writing a unit test for an autoloader when I came across a somewhat unintuitive behavior in PHPUnit.

One requirement of the test suite was that some test methods had to be run in a separate process since class declarations reside in the global scope and persist until the process terminates. So, I slapped a @runInSeparateProcess annotation in the docblock of a test method with that requirement, ran the test suite… and watched that test method fail because the class was still being declared.

It took some head-scratching and tracing through the source of PHPUnit itself to figure out what was going on. When you run the phpunit executable, it’s actually instantiating PHPUnit_TextUI_TestRunner. The eventual result of this is that the run() method inherited by your subclass of PHPUnit_Framework_TestCase is called.

Depending on the value of the also-inherited $preserveGlobalState instance property, which can be set via the setPreserveGlobalState() method, multiple measures are undertaken to preserve the state of the current process. One such measure is including files for all the classes currently defined in that process, which is what was tripping me up because $preserveGlobalState has a default value of true.

$preserveGlobalState must contain its intended value before the run() method is called. The easiest way that I’ve found to facilitate this is to override the run() method in your subclass, call setPreserveGlobalState() there, then call the parent class implementation of run(). I’ve included a code sample below to illustrate this.

class MyTestCase extends PHPUnit_Framework_TestCase
    public function run(PHPUnit_Framework_TestResult $result = NULL)
        return parent::run($result);

So, if you try to use the @runInSeparateProcess or @runTestsInSeparateProcesses annotations that PHPUnit offers, be aware that the global state will be preserved by default. You will need to explicitly set it to not be so if running tests in separate processes is to have the effect that you are probably intending.

Database Testing with PHPUnit and MySQL

Update 2012/01/15: I finally got around to submitting a patch to document this feature in the PHPUnit manual. Sebastian has merged it, so it will hopefully be available in the online manual soon.

Update #2 2012/01/23: I got around to checking the online version of the manual and the current build includes my patch. Enjoy.

I recently made a contribution to the PHPUnit project that I thought I’d take a blog post to discuss. One of the extensions bundled with PHPUnit adds support for database testing. This extension was contributed by Mike Lively and is a port of the DbUnit extension for the JUnit Java unit testing framework. If you’re interested in learning more about database unit testing, check out this presentation by Sebastian Bergmann on the subject.

One of the major components of both extensions is the data set. Database unit tests involve loading a seed data set into a database, executing code that performs an operation on that data set such as deleting a record, and then checking the state of the data set to confirm that the operation had the desired effect. DbUnit supports multiple formats for seed data sets. The PHPUnit Database extension includes support for DbUnit’s XML and flat XML formats plus CSV format as well.

If you’re using MySQL as your database, CSV has been the only format supported by both the mysqldump utility and the PHPUnit Database extension up to this point. My contribution adds support for its XML format to the extension. While this support was developed to work in the PHPUnit 3.4.x branch, it won’t be available in a stable release until 3.5.0. In the meantime, this is how you can use it now.

  1. Go to the commit on Github and apply the additions and modifications included in it to your PHPUnit installation.
  2. From a shell, get your XML seed data set and store it in a location accessible to your unit test cases.
    mysqldump --xml -t -u username -p database > seed.xml
  3. Create a test case class that extends PHPUnit_Extensions_Database_TestCase. Implement getConnection() and getDataSet() as per the documentation where the latter will include a method call to create the data set from the XML file as shown below.
    $dataSet = $this->createMySQLXMLDataSet('/path/to/seed.xml');
  4. At this point, you can execute operations on the database to get it to its expected state following a test, produce an XML dump of the database in that state, and then compare that dump to the actual database contents in a test method to confirm that the two are equal.
    $expected = $this->createMySQLXMLDataSet('/path/to/expected.xml');
    $actual = new PHPUnit_Extensions_Database_DataSet_QueryDataSet($this->getConnection());
    // Specify a SELECT query as the 2nd parameter here to limit the data set, else the entire table is used
    $this->assertDataSetsEqual($expected, $actual);

That’s it! Hopefully this proves useful to someone else.

PHPUnit and Xdebug on Ubuntu Karmic

This is just a quick post to advise anyone who may be using PHPUnit and Xdebug together on Ubuntu Karmic. If you try to upgrade to PHPUnit 3.4.6 and you’re using the php5-xdebug Ubuntu package (which is Xdebug 2.0.4), you may get output that looks like this:

$ sudo pear upgrade phpunit/PHPUnit
Did not download optional dependencies: pear/Image_GraphViz, pear/Log, use --alldeps to download automatically
phpunit/PHPUnit can optionally use package "pear/Image_GraphViz" (version >= 1.2.1)
phpunit/PHPUnit can optionally use package "pear/Log"
phpunit/PHPUnit can optionally use PHP extension "pdo_sqlite"
phpunit/PHPUnit requires PHP extension "xdebug" (version >= 2.0.5), installed version is 2.0.4
No valid packages found
upgrade failed

There are two ways to deal with this situation. First off, note that the newer Xdebug 2.0.5 version includes several bugfixes including one related to code coverage reporting. That said, if you still want to continue using the php5-xdebug package anyway, you can force the upgrade by having the PEAR installer ignore dependencies like so:

sudo pear upgrade -n phpunit/PHPUnit

The other method involves installing Xdebug 2.0.5. First, if you have the php5-xdebug package, remove it.

sudo apt-get remove php5-xdebug

Next, use the PECL installer to install Xdebug. This requires that you have the php5-dev package installed so that the extension can be compiled locally.

sudo apt-get install php5-dev
sudo pecl install xdebug

At this point, create the file /etc/php5/conf.d/xdebug.ini if it doesn’t already exist and populate it with these contents:


Then bounce Apache so that the new extension will be loaded.

sudo apache2ctl restart

That’s it. Hope someone finds this helpful.