/**
* Replaces function in provided namespace with user-defined function or value that function returns.
* Function is restored to original on cleanup.
*
* ```php
* <?php
* namespace demo;
* test::func('demo', 'date', 2004);
* date('Y'); // 2004
*
* test::func('demo', 'date', function($format) {
* if ($format == 'Y') {
* return 2004;
* } else {
* return \date($param);
* }
* }
*
* ```
*
* Mocked functions can be verified for calls:
*
* ```php
* <?php
* namespace demo;
* $func = test::func('demo', 'date', 2004);
* date('Y'); // 2004
* $func->verifyInvoked();
* $func->verifyInvokedOnce(['Y']);
* ```
*
* @param string $namespace
* @param string $functionName
* @param mixed $body whatever a function might return or Callable substitute
* @return Proxy\FuncProxy
*/
public static function func($namespace, $functionName, $body)
{
Core\Registry::registerFunc($namespace, $functionName, $body);
return new Proxy\FuncProxy($namespace, $functionName);
}
