Why can test private methods/fields in Spock without problems?

Question

package com.example.dev;
public class AClass {
 private Integer a =10;
...//other code
}

and when I try to access a in my Spock method:

Answer 1

Spock isn't guilty, it's groovy itself, see: Private method in groovy is not private.

While it's possible to refer to private members of class, it's definitely not a good practice.

Answer 2

It's my understanding that

aClassVar.a = new Integer(100)

in Groovy / Spock is just syntactic sugar for

aClassVar.setA(new Integer(100));

in Java. There have been occasions where I tried to do that and there WASN'T a setter and Spock griped.

As for why we create private attributes and then give them setters, THAT is another discussion.