JUnit mocking method call - junit

Question

I am writing a Junit test for a method 'methodA' which is in class 'classA'. In 'methodA' another method 'methodB' of class 'classB' is called. The 'methodB' calls soap web-service. I want to mock this methodB soap web-service call. In this case i am calling classA.methodA. Here i don't find a way that at the time when classB.methodB is called then mock value should get updated. I went through many links about Mockito, but they all refer on updating the mock value from junit class only. So, how can i pass mocked value their.
#Test
public void junitTest() {
String arg1 = "arg1";
classA aObj = new classA();
aObj.methodA(arg1);
}
public classA {
public string methodA(String arg1) {
classB bObj = new classB();
bObj.methodB();
//somwthing on arg1
return result;
}
}
public classB {
public list methodB() {
//web-service call
return list from web - service.
}
}

Answer 1

I am writing a Junit test for a method methodA which is in class
classA
Since you are unit testing methodA of classA, you should be focusing on mocking just the bObj.methodB(); call. You should not get into what it does or doesn't internally.
Not you are creating classB object in methodA which is not the ideal scenario. You should make bObj as the instance variable of classA with appropriate getter, setters and constructor.
Then from you testing class set this classB dependency.
You should structure your code and something tests like this:
class classAMicroTest {
#Test
public void junitTest() {
String arg1 = "arg1";
classA aObj = new classA();
classB mockedBobj = Mockito.mock(classB.class);
Mockito.when(mockedBobj.methodB()).thenReturn(new ArrayList<>());
aObj.setbObj(mockedBobj);
aObj.methodA(arg1);
Mockito.verify(mockedBobj, times(1)).methodB());
}
}
class classA {
classB bObj;
public void setbObj(classB bObj) {
this.bObj = bObj;
}
public String methodA(String arg1) {
bObj.methodB();
// somwthing on arg1
return result;
}
}
class classB {
public List<String> methodB() {
return new ArrayList<>();
}
}