Mockito.mock(null)

Weshalb sollte das sinn machen?

Mockito.when(null).thenReturn(meinObjekt)

bedeutet eigentlich: Liebes Mockito. Nimm den letzten Aufruf auf irgend einem Mock. Wenn irgendwann derselbe Aufruf mit denselben Parametern gemacht werden sollte, dann gib „meinObjekt“ zurück.

Dies wird unten demonstriert.

import org.mockito.Mockito;

import java.util.Objects;

/**
 * Demonstrates how Mockito.when(null) can be used to tell Mockito to 
 * return a given value if  objects equals to given ones are passed to the mocked method 
 */
public class HPTest {
    public static void main(String[] args) {
        MyObj mockedObject = Mockito.mock(MyObj.class);
        
        /* Tell Mockito, that if get1() is called, then return "super cool string 1.1"*/
        mockedObject.get1();
        Mockito.when(null).thenReturn("super cool string 1.1");
        mockedObject.get2();
        Mockito.when(null).thenReturn("super cool string 2");
        System.out.println(mockedObject.get1());
        System.out.println(mockedObject.get1());
        System.out.println(mockedObject.get2());
        System.out.println(mockedObject.toString());


        /* Tell Mockito, that if return1("1") is called, then return "Return 1" */
        mockedObject.return1("1");
        Mockito.when(null).thenReturn("Return 1");

        /* but if return1("2") is called, then return "Return 2" */
        mockedObject.return1("2");
        Mockito.when(null).thenReturn("Return 2");

        System.out.println(mockedObject.return1("1"));
        System.out.println(mockedObject.return1("2"));
        System.out.println(mockedObject.return1("2"));
        System.out.println(mockedObject.return1("1"));

        mockedObject.returnOnObj(new Bohne("A"));
        Mockito.when(null).thenReturn("On Obj A");

        mockedObject.returnOnObj(new Bohne("B"));
        Mockito.when(null).thenReturn("On Obj B");

        System.out.println(mockedObject.returnOnObj(new Bohne("A")));
        System.out.println(mockedObject.returnOnObj(new Bohne("B")));
        System.out.println(mockedObject.returnOnObj(new Bohne("B")));
        System.out.println(mockedObject.returnOnObj(new Bohne("A")));
    }

}
class MyObj {
    public String get1(){return "not mocked 1";}
    public String get2(){return "not mocked 2";}
    public String return1(String in){return  "not mocked";}
    public String returnOnObj(Bohne in){return  "not mocked";}
}
class Bohne {
    public String id;

    public Bohne(String id) {
        this.id = id;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Bohne)) return false;
        Bohne bohne = (Bohne) o;
        return Objects.equals(id, bohne.id);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id);
    }
}
/*
Output:
super cool string 1.1
super cool string 1.1
super cool string 2
Mock for MyObj, hashCode: 650023597
Return 1
Return 2
Return 2
Return 1
On Obj A
On Obj B
On Obj B
On Obj A

Process finished with exit code 0
 */