Question

I’m writing a unit testing platform and I want to be able to dynamically generate a function based off of each function in the web service I am testing. The dynamic function would be generated with default(correct) values for each argument in the web service and allow them to be easily traded out with incorrect values for error testing.

$arrayOfDefVals = array(123, 'foo');

testFunctionGenerator('function1', $arrayOfDefVals);

//resulting php code:
function1Test($expectedOutput, $arg1=123, $arg2='foo')
{
    try
    {
        $out = function1($arg1, $arg2);
        if($expectedOutput === $out)
            return true;
        else
            return $out;
    } 
    catch ($e) 
    {
        return $e;
    } 
}

This would allow me to quickly and cleanly pass one bad argument, or any number of bad arguments, at a time to test all of the error catching in the web service.

My main question is:
Is this even possible with php?
If it’s not possible, is there an alternative?

EDIT: I’m not looking for a unit test, I’m trying to learn by doing. I’m not looking for advice on this code example, it’s just a quick example of what I would like to do. I just want to know if it’s possible.

Answer 1

I would not try that first as PHP has not build-in macro support. But probably something in that direction:

function function1($param1, $param2)
{
    return  sprintf("param1: %d, param2: '%s'\n", $param1, $param2);
}

/* Macro: basically a port of your macro as a function */

$testFunctionGenerator = function($callback, array $defVals = array())
{
    $defVals = array_values($defVals); // list, not hash
    return function() use ($callback, $defVals)
    {
        $callArgs = func_get_args();
        $expectedOutput = array_shift($callArgs);

        $callArgs += $defVals;

        return $expectedOutput == call_user_func_array($callback, $callArgs);
    };
};

/* Use */

$arrayOfDefVals = array(123, 'foo');

$function1Test = $testFunctionGenerator('function1', $arrayOfDefVals);

var_dump($function1Test("param1: 456, param2: 'foo'\n", 456)); # bool(true)

Probably this is helpful, see Anonymous functions^­Docs, func_get_args^­Docs, the Union array operator^­Docs and call_user_func_array^­Docs.