The error_reporting() function sets the error_reporting directive at runtime. PHP has many levels of errors, using this function sets that level for the duration (runtime) of your script. If the optional level is not set, error_reporting() will just return the current error reporting level. Some examples are given hereafter:

// Turn off all error reporting
error_reporting(0);

// Report simple running errors
error_reporting(E_ERROR | E_WARNING | E_PARSE);

PHP-Developers appreciate the 

// Reporting E_NOTICE can be good too (to report uninitialized variables or catch variable name misspellings ...)
error_reporting(E_ERROR | E_WARNING | E_PARSE | E_NOTICE);

// Report all errors except E_NOTICE
// This is the default value set in php.ini
error_reporting(E_ALL ^ E_NOTICE);

// Report all PHP errors
error_reporting(E_ALL);

PHP-Developers appreciate SimpleTest, a PHP unit test and web test framework. The most recent version is 1.0.1 released 2008-04-08, available at SourceForge. JAVA-Developers are  familiar with JUnit, originally written by Erich Gamma and Kent Beck. SimpleTest Interfaces are similar to JUnit.