Want to mock a method which is calling another class method-CodePudding

I am new to mockito using it for unit testing. I need some help to understand mock a method.I have a method - method1() of class A which needs to be tested .Here i want to verify that execute() is executed (Interaction testing).Below is the method.

class A{
void method1(){

  B b = new B(org_id);

  b.execute();


 }
}

 Class B {
    B(String orgId){
    this.orgId = org_id;
    }
    
    void execute(){
     String x = Dependency.m1();
    
     String y = Dependency.m2();
    
     }
    
     static class Dependency{
    
     public String m1(){

       return K.someText();

      }
    
     public String m2(){

      return K.someText();

     }
    }
   }

Could anyone help me how to achieve it?TIA

CodePudding user response：

As here you are not using any dependency injection, you cannot mock and inject that object into the test class using mocikto. You can look at this answer here :- Java Mock object, without dependency injection

CodePudding user response：

Make B an instance variable of A, add a constructor for A, pass the mock to constructor.

class A{
B b;
public A(B b){
  this.b = b;
 }
}

in test class

A a = new A(Mockito.mock(B.class));

CodePudding user response：

Since you create a new instance of B, you could parameterize A with a Function<String, B> (a factory method, or just B::new which you can the mock in your test.

class A {
 final Function<String, B> bCreator;
 A(Function<String, B> bCreator) {
   this.bCreator = bCreator;
 }
 void method1(){
  B b = bCreator.apply(orgId);
  b.execute();
 }
}

// test
B b = mock(B.class);
Function<String, B> bCreator = mock(Function.class);
when(bCreator.apply(any()).thenReturn(b);
A a = new A(bCreator);
a.method1();
verify(b).execute();

The test whether B::execute works correctly (ie calls the appropriate dependency methods) should be done in another test since it's another unit.