In order to set up tests and run code coverage, you need to have certain software on your local Mac.

  1. Composer—to download test libraries and PHPUnit
  2. Xdebug or PCOV—to generate code coverage
  3. Node.js—if you want to write JS tests for your projects

While Composer and Node should be installed on your computer by now, the Xdebug module is most probably not installed.

Installing Xdebug

Assuming you have installed the latest stable PHP version using Homebrew, you should use pecl to install the Xdebug. Pecl is a repository for PHP extensions. First, make sure you have it installed (even though it comes with the Homebrew PHP version).

which pecl


Try to install xdebug

pecl install xdebug

That can be done in two ways: your installation passes, and you get a message like this

Successful installation


Build process completed successfully
Installing '/usr/local/Cellar/php/7.3.7/pecl/20180731/'
install ok: channel://
Extension xdebug enabled in php.ini

In this case, all you need to check is if PHP has linked the module correctly.

php -v

PHP 7.3.7 (cli) (built: Aug  5 2019 02:51:04) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.7, Copyright (c) 1998-2018 Zend Technologies
    with Xdebug v2.7.2, Copyright (c) 2002-2019, by Derick Rethans
    with Zend OPcache v7.3.7, Copyright (c) 1999-2018, by Zend Technologies

If you get an error message, you'll need to find your php.ini file

php -i | grep .ini

Configuration File (php.ini) Path => /usr/local/etc/php/7.3
Loaded Configuration File => /usr/local/etc/php/7.3/php.ini
Scan this dir for additional .ini files => /usr/local/etc/php/7.3/conf.d
Additional .ini files parsed => /usr/local/etc/php/7.3/conf.d/ext-opcache.ini
user_ini.cache_ttl => 300 => 300
user_ini.filename => .user.ini => .user.ini
Supported handlers => ndbm cdb cdb_make inifile flatfile
com_init_db => 0
Classes => AppendIterator, ArrayIterator, ArrayObject, BadFunctionCallException, BadMethodCallException, CachingIterator, CallbackFilterIterator, DirectoryIterator, DomainException, EmptyIterator, FilesystemIterator, FilterIterator, GlobIterator, InfiniteIterator, InvalidArgumentException, IteratorIterator, LengthException, LimitIterator, LogicException, MultipleIterator, NoRewindIterator, OutOfBoundsException, OutOfRangeException, OverflowException, ParentIterator, RangeException, RecursiveArrayIterator, RecursiveCachingIterator, RecursiveCallbackFilterIterator, RecursiveDirectoryIterator, RecursiveFilterIterator, RecursiveIteratorIterator, RecursiveRegexIterator, RecursiveTreeIterator, RegexIterator, RuntimeException, SplDoublyLinkedList, SplFileInfo, SplFileObject, SplFixedArray, SplHeap, SplMinHeap, SplMaxHeap, SplObjectStorage, SplPriorityQueue, SplQueue, SplStack, SplTempFileObject, UnderflowException, UnexpectedValueException
open sourced by =>

Go to /usr/local/etc/php/7.3/php.ini and edit it by adding


at the end of the php.ini file.

That's it, you're ready to go.

Unsuccessful installation

When installing Xdebug, you might get the following error

Build process completed successfully
Installing '/usr/local/Cellar/php/7.3.7/pecl/20180731/'

Warning: mkdir(): File exists in System.php on line 294
PHP Warning:  mkdir(): File exists in /usr/local/Cellar/php/7.3.7/share/php/pear/System.php on line 294

Warning: mkdir(): File exists in /usr/local/Cellar/php/7.3.7/share/php/pear/System.php on line 294
ERROR: failed to mkdir /usr/local/Cellar/php/7.3.7/pecl/20180731

Go to your php installation folder (/usr/local/Cellar/php/7.3.7/, for instance) and type

ls -all

total 168
-rw-r--r--   1 infinum-denis  staff   3.1K Aug  7 10:10 INSTALL_RECEIPT.json
-rw-r--r--   1 infinum-denis  staff   3.1K Jul  3 13:30 LICENSE
-rw-r--r--   1 infinum-denis  staff    64K Jul  3 13:30 NEWS
-rw-r--r--   1 infinum-denis  staff   1.6K Jul  3 13:30
drwxr-xr-x  12 infinum-denis  staff   384B Aug  7 10:10 bin
-rw-r--r--   1 infinum-denis  staff   628B Aug  7 10:10 homebrew.mxcl.php.plist
drwxr-xr-x   3 infinum-denis  staff    96B Jul  3 13:30 include
drwxr-xr-x   4 infinum-denis  staff   128B Jul  3 13:30 lib
lrwxr-xr-x   1 infinum-denis  staff    23B Aug  7 10:10 pecl -> /usr/local/lib/php/pecl
drwxr-xr-x   3 infinum-denis  staff    96B Jul  3 13:30 sbin
drwxr-xr-x   4 infinum-denis  staff   128B Jul  3 13:30 share

You can see that pecl is symlinked to /usr/local/lib/php/pecl, but which pecl specified /usr/local/bin/pecl, which is itself a symlink to /usr/local/Cellar/php/7.3.7/bin/pecl. So you need to remove the symlink

unlink pecl

Now you can install Xdebug again, and it should work as described in the previous case (follow the steps described above to add it correctly in your php.ini).

Possible side effects

A possible side effect of running Xdebug, especially if you enable profiler output in Xdebug settings in php.ini, is that that file can grow very large. To prevent this, just make sure you delete it every once in a while, or simply don't enable logging.

Installing PCOV

The problem with using Xdebug to generate code coverage is that it's primarily a debugging tool. That means that it adds a huge overhead when generating code coverage. Which ultimately means that the tests take a long time to execute (when generating code coverage).

Luckily for us there is a way to shorten that time and use less memory. PCOV is a self contained CodeCoverage compatible driver for PHP7. By default it comes enabled on PHPUnit8, but since PHPUnit8 has introduced some typehints only compatible with PHP 7.2 (or newer), that means that we cannot (yet) use it for running the tests.

We can install PCOV as an extension, and use pcov-clobber to run it on PHPUnit7.

You can install PCOV using pecl

pecl install pcov

Or by cloning it and compiling it manually

git clone
cd pcov
./configure --enable-pcov
make test
make install

Then you need to add to your php.ini

extension=/usr/local/Cellar/php/7.3.7/pecl/20180731/ # This can vary on your system
pcov.enabled = 1

Finally, using composer install the pcov-clobber in your project

composer require pcov/clobber --dev

and run vendor/bin/pcov clobber.

Be sure to disable the Xdebug extension in your php.ini (you can comment it using ;).