BusinessService.java

/*
* Business logic service
*/
public class MyBusinessService {

	private SomeService someService;
	
	public void executeSomeLogic(String input) {
	
		Something thing = new Something();
		
		if(input.equals("A") {
			// ...do some logic here
		} if else (input.equals("B") {
			// ...or something here
		} if else (input.equals("C") {
			// ....or something else here
		}

		someService.doSomething(thing);
	
	}

}

/*
* Business Logic Test
*/
@RunWith(MockitoJUnitRunner.class)
public class MyBusinessServiceTest {
	
	@Mock
	private SomeService someService;
	
	@InjectMocks
	private MyBusinessService myBusinessService;
	
	@Captor
	private ArgumentCaptor<Something> somethingCaptor;
	
	@Test
	public void testExecuteSomeLogic_Scenario1() {
			
		String input = "A";
		myBusinessService.executeSomeLogic(input);
		
		verify(someService).doSomething(somethingCaptor.capture()); 
		// ...assert captured values here
	}
	
	@Test
	public void testExecuteSomeLogic_SCenario2() {
				
		String input = "B";
		myBusinessService.executeSomeLogic(input);
		
		verify(someService).doSomething(somethingCaptor.capture()); 
		// ...assert captured values here
	}
	
	@Test
	public void testExecuteSomeLogic_SCenario3() {
				
		String input = "C";
		myBusinessService.executeSomeLogic(input);
		
		verify(someService).doSomething(somethingCaptor.capture()); 
		// ...assert captured values here
	}
	
}