I have the following code (simplified and details changed for this question):
class model_to_be_tested {
// an array that holds a collection of thing A
public $array_of_thing_A;
// already doing constructor injection for the data object
public __construct($data_object) {
// details here
}
public function add_new_thing_A($has_relationship) {
$thing_A = new Thing_A();
$thing_A->is_thing = true;
$thing_A->has_relationship_with_thing_B = $has_relationship;
if ($has_relationship) {
$thing_B = new Thing_B();
$thing_A->relationship_with = $thing_B;
}
$this->array_of_thing_A[] = $thing_A;
}
}
In the above example, I have to decouple the instantiation of Thing_A and Thing_B from the add_new_thing method. However, a simple constructor injection will not do for these two classes. This is because I need fresh instances of Thing_A and Thing_B every time add_new_thing is called so that Thing_A can be added to the array_of_thing_A.
How can I make this function unit testable? And more specifically for me to use mocks of Thing_A and Thing_B in testing this function in PHPUnit?
Any suggestions with code example will be appreciated.
Additionally, I would like to mention that Thing_A and Thing_B are used elsewhere in the codebase that I am working with and the code using these classes will eventually need to be unit tested. Solutions that are too localized and would cause repeated code elsewhere will not be too ideal in my situation. Thank you.