I've been playing with PHPUnit a lot of late, particularly with framework development. One thing that's always hard to determine is how well your code is exercised — basically, how much of the code is tested in the unit tests?

In PHPUnit 3, you can now generate code coverage reports using XDebug, and the usage is very simple:

matthew@localhost:~/dev/zend/framework-svn/tests$ phpunit --report ~/tmp/report AllTests

The above command creates a coverage report directory report under my tmp directory. You can then browse through the reports in a web browser and visually see which lines of code were executed during tests, and which were not, as well as a synopsis showing the percentage of coverage for any given file or directory — useful stuff indeed!

So, what's the problem? Getting XDebug running.

The executive summary:

• Enable the extension using zend_extension = /full/path/to/xdebug.so, not as extension = xdebug.so, in your php.ini

• Use the setting xdebug.default_enable = Off in your php.ini.

• If compiling using pecl or pear, make sure it compiles against the correct PHP; if not, hand compile it using:

  $ /path/to/phpize
  $ ./configure --with-php-config=/path/to/php-config
  $ make
  $ make install
  

For the detailed narrative, read on.

First off, I tried installing XDebug using pecl and pear. Even though my pear config-show showed my correct PHP install and extension directory, for some reason it found the PHP 4.4.1 installation I have elsewhere in the filesystem, and it compiled against that. So, I followed the directions for compiling by hand, and all was mostly well. I discovered, however, that you need to specify the --with-php-config=/path/to/php-config switch to ensure that it uses the appropriate php-config (particularly if you have multiple PHP installs on your system).

Next up was getting it to work with PHP. I edited my php.ini file, and did a standard extension=xdebug.so. What was odd is that I then showed xdebug as present (using php -m), but not as a Zend extension. I tried zend_extension=xdebug.so, but then nothing showed. Then, in the end, I followed the instructions, and used zend_extension=/full/path/to/xdebug.so, and it was available.

Okay, let's test it out… I started running tests and… segmentation fault. Disabling the extension brought everything back to normal… only when enabled did the segmentation fault occur. I decided to look at the xdebug php.ini settings to see what I could find.

After some trial and error, I discovered that setting xdebug.default_enable = Off fixed the issue, and I was able to start generating some wonderful coverage reports.

Now, to write more tests…