public function test_get_user_directory()
{
// Test for OS Default.
$this->assertTrue(is_writable(util::get_user_directory()));
$oldServer = $_SERVER;
unset($_SERVER);
// Test for UNIX.
$_SERVER['HOME'] = '/home/unknown';
$this->assertEquals($_SERVER['HOME'], util::get_user_directory(), 'Could not get the user\'s home directory in UNIX.');
unset($_SERVER);
// Test for Windows.
$expected = 'X:\\Users\\ThisUser';
$_SERVER['HOMEDRIVE'] = 'X:';
$_SERVER['HOMEPATH'] = '\\Users\\ThisUser';
$this->assertEquals($expected, util::get_user_directory(), 'Could not get the user\'s home directory in Windows.');
// In case the tests are not being run in isolation.
$_SERVER = $oldServer;
}