I would like to redefine certain functions in PHP that are already built for example, echo() or time() - I don't need to define these functions globally, just within a single script for testing.
I think this can be done in Perl but in PHP - Is this possible?
runkit_function_redefine ― Replace a function definition with a new implementation
Note: By default, only userspace functions may be removed, renamed, or modified. In order to override internal functions, you must enable the runkit.internal_override setting in php.ini.
You might also want to check out
override_function() ― Overrides built-in functions
from the Advanced PHP debugger package.
Having to redefine native PHP functions or language statements should ring an alarm bell though. This should not be part of your production code in my opinion, unless you are writing a debugger or similar tool.
Another option would be to use http://antecedent.github.io/patchwork
Patchwork is a PHP library that makes it possible to redefine user-defined functions and methods at runtime, loosely replicating the functionality
runkit_function_redefinein pure PHP 5.3 code, which, among other things, enables you to replace static and private methods with test doubles.
The latter doesn't work for native functions though
echo is not a function, it's a language construct. I don't have anything for that.
But function calls like time() can be overridden since PHP-5.3's namespace fallback policy:
For functions […], PHP will fall back to global functions […] if a namespaced function […] does not exist.
E.g. for the unqualified function call time() in the non global namespace foo you can provide foo\time().
Personally I'm using this to mock e.g. time() for unit test. I published those mocks in the library PHP-Mock:
namespace foo; use phpmock\phpunit\PHPMock; class FooTest extends \PHPUnit_Framework_TestCase { use PHPMock; public function testBar() { $time = $this->getFunctionMock(__NAMESPACE__, "time"); $time->expects($this->once())->willReturn(3); $this->assertEquals(3, time()); } }