thenThrow() not throwing an exception - spring-boot

Question

I have a method in OneServiceImpl class as follows. In that class I am calling an interface method from another class.
public class OneServiceImpl {
//created dependency
final private SecondService secondService;
public void sendMessage(){
secondService.validateAndSend(5)
}
}
public interface SecondService() {
public Status validateAndSend(int length);
}
public class SecondServiceImpl {
#Override
public Status ValidateAndSend(int length) {
if(length < 5) {
  throw new BadRequestException("error", "error");
}
}
}
Now when I am try to perform unit test on OneServiceImpl I am not able to throw a BadRequestException.
when(secondService.validateAndSend(6)).thenThrow(BadRequestException.class);

Answer 1

Not quite sure what your use case is, but I think you should write an own test to accept and test an exception.
#Test(expected = BadRequestException.class)
public void testValidateAndSend(){
SecondService secondService = new SecondService();
secondservice.ValidateAndSend(6); //method should be lowercase
}

Answer 2

Not sure this is the case considering you didn't post a full example of code + unit tests, but your mock will throw only when you are passing 6 as parameter. When configuring the behaviour of your mock with when you are telling it to throw only when the validateAndSend method is called with parameter 6.
when(secondService.validateAndSend(6)).thenThrow(...)
In your code you have 5 hardcoded. So that mock will never throw for the code you have, because it's configured to react to an invocation with parameter 6 but the actual code is always invoking it passing 5.
public void sendMessage(){
secondService.validateAndSend(5)
}
If the value passed to the mock is not important you could do something like the following, that will throw no matter what's passed to it:
when(secondService.validateAndSend(any())).thenThrow(BadRequestException.class);
On the other hand, if the value is important and it has to be 5 you could change the configuration of your mock with:
when(secondService.validateAndSend(5)).thenThrow(BadRequestException.class)