{"id":807,"date":"2012-12-03T13:23:16","date_gmt":"2012-12-03T13:23:16","guid":{"rendered":"http:\/\/www.nathankowald.com\/blog\/?p=807"},"modified":"2016-11-13T16:58:50","modified_gmt":"2016-11-13T16:58:50","slug":"how-to-unit-test-private-methods-in-php","status":"publish","type":"post","link":"https:\/\/www.nathankowald.com\/blog\/2012\/12\/how-to-unit-test-private-methods-in-php\/","title":{"rendered":"Unit test private methods in PHP"},"content":{"rendered":"

Requires:<\/strong> PHP 5.3.2 or greater.
\nIf you’re not running 5.3.2+ you can test private methods indirectly by creating a public method, that calls your private method.<\/p>\n

\n↓ Jump to solution<\/a>\n<\/div>\n

Problem<\/h2>\n

We have a class, StatFinder<\/strong> which contains a private method, getDomainFromEmail()<\/strong> that we want to test.<\/p>\n

\r\n<?php\r\nclass StatFinder\r\n{\r\n    \/\/ Get domain from email address\r\n    private function getDomainFromEmail($email='')\r\n    {\r\n        if ($email == '') return '';\r\n        $parts = explode('@', $email);\r\n        if ($parts === false || !isset($parts[1])) return '';\r\n\r\n        return $parts[1];\r\n    }\r\n}<\/pre>\n
We create a test to check that calling getEmailFromDomain(‘iliketurtles@gmail.com’)<\/strong> returns the expected ‘gmail.com<\/strong>‘. I’m using PHPUnit<\/a> to run the unit test.<\/p>\n
\r\n<?php\r\ninclude('..\/libraries\/StatFinder.php');\r\n\r\nclass StatFinderTest extends PHPUnit_Framework_TestCase\r\n{\r\n    public function testGetDomainFromEmail()\r\n    {\r\n        $sf = new StatFinder();\r\n        $email = 'iliketurtles@gmail.com';\r\n        $expected = 'gmail.com';\r\n        $this->assertEquals($expected, $sf->getDomainFromEmail($email));\r\n    }\r\n}<\/pre>\n
When run, the test fails because the method is private, so only accessible by the class that defined it.<\/p>\n
\"\"<\/a>
\nFailed unit test – (PHPUnit running in PhpStorm)<\/em>
\n<\/a><\/p>\n
Solution<\/h2>\n
You can test private and protected methods by using the ReflectionMethod class, part of the Reflection API<\/a> that comes with PHP 5.
\nThe setAccessible<\/a> method of the ReflectionMethod class is only available from PHP 5.3.2 up so you’ll have to be running at least this to use this.<\/p>\n
\r\n<?php\r\ninclude('..\/libraries\/StatFinder.php');\r\n\r\nclass StatFinderTest extends PHPUnit_Framework_TestCase\r\n{\r\n    public function testGetDomainFromEmail()\r\n    {\r\n        $method = new ReflectionMethod('StatFinder', 'getDomainFromEmail');\r\n        $method->setAccessible(true);\r\n\r\n        $email = 'iliketurtles@gmail.com';\r\n        $expected = 'gmail.com';\r\n        $this->assertEquals($expected, $method->invoke(new StatFinder, $email));\r\n    }\r\n}<\/pre>\n
Explanation<\/h2>\n
\r\n<?php\r\n$method = new ReflectionMethod('StatFinder', 'getDomainFromEmail');<\/pre>\n
This creates an instance of the ReflectionMethod class.
\nThe first argument, StatFinder<\/strong> is the class that contains the private method to test.
\nThe second argument, getDomainFromEmail<\/strong> is the method to test.<\/p>\n
\r\n<?php\r\n$method->setAccessible(true);<\/pre>\n
setAccessible(true)<\/strong> allows the private method, getDomainFromEmail<\/strong> to be called from inside the test.<\/p>\n
\r\n<?php\r\n$this->assertEquals($expected, $method->invoke(new StatFinder, $email));<\/pre>\n
invoke()<\/strong> invokes the private method.
\nThe first argument, new StatFinder<\/strong> is the object to invoke the method on. For static methods, pass null.
\nThe second argument, $email<\/strong> is the argument to pass to the method. Zero or more arguments can be passed to the method this way.<\/p>\n
We run our updated test and it now works.<\/p>\n
\"\"<\/a>
\nSuccessful test<\/em><\/p>\n
Related<\/h2>\n