Question

I have a class structure like this:

class A {
    public someFunction() {
        $objectB = new B();
        $result = $objectB->getResult();
        return $result;
    }
}

I am writing the unit test for someFunction() that belongs to class A. However, it depends on class B. I can mock someFunction() but how can I resolve the dependency on class B? I want to mock class B automatically.

Answer 1

Use dependency injection: either provide a method to set the B object, or pass the b object optionally to someFunction().

Original code

class A {
    public function someFunction() {
        $objectB = new B();
        $result = $objectB->getResult();
        return $result;
    }
}

Optional parameter

class A {
    public function someFunction($objectB = null) {
        if ($objectB == null) { $objectB = new B(); }
        $result = $objectB->getResult();
        return $result;
    }
}

Setter method

class A {
    protected $b;


    public function __construct() {
        $this->b = new B();
    }

    public function setB($b) {
        $this->b = $b;
    }

    public function someFunction() {
        $result = $this->b->getResult();
        return $result;
    }
}