How to test function with nonexist callback class as parameter - php

Question

I have following problem. I doing API for our web and customer must use his function as callback in my function.
Example:
UserClass {
userMethod() {
return $data;
}
}
MyClass {
myFunction (callback ) {
doingSomething();
doingSomething();
$data = call_user_function($callback);
return doingSomethingWithData($data);
}
}
Problem is, that this is API and I cant implement customer class as callback, because non exist, but i need test that function will be work with expected data. Is there any possibilites how test my function using phpunit?
Thanks a lot

Answer 1

Just pass in anonymous function that returns expected result the one you can predict output for. Make sure that it handles garbage data out/edge cases properly.
Your test can look something like that:
class MyClassTest extends PHPUnit_Framework_TestCase
{
/**
* #dataProvider myFunctionProvider
*/
public function testMyFunction($callback, $expected)
{
$this->assertEquals(
// Just as example you can create instance of class and call it.
MyClass::MyFunction($callback),
$expected
);
}
public function myFunctionProvider()
{
return [
[ function () { return 'a';}, 'a'],
[ function () { return 'c';}, 'c'],
[ function () { return 'b';}, 'b']
];
}
}
As a side note change your code to:
function MyFunc(callable $callback) {
}
That'll make sure you get only callable in to your function.