Junit test case not running for mock JPA - junit

Question

I have written sample CRUD methods.I have written JUnit test cases for Service component but getting "address id not found.." when I run the test.
#Test
public void updateAddressTest() throws ResourceNotFoundException {
Optional<Person> p = Optional.ofNullable(new Person( "Pranya", "Pune"));
when(personRepository.existsById(1L)).thenReturn(true);
Optional<Address> address = Optional.ofNullable(new Address( "zzz", "hyd","tel","1234"));
when(repository.findById(1L)).thenReturn(address);
Address addr1 = new Address( "zzz", "hyd","tel","1234");
when(repository.save(addr1)).thenReturn(addr1);
Address add= service.updateAddress(new Long(1L), new Long(1L),addr1);
assertEquals(addr1,add );
}
#Service
public class AddressService {
#Autowired
private AddressRepository repository;
#Autowired
private PersonRepository personRepository;
public Address updateAddress(Long personId,
Long addressId,Address addrRequest) throws ResourceNotFoundException {
if (!personRepository.existsById(personId)) {
throw new ResourceNotFoundException("personId not found");
}
return repository.findById(addressId).map(address -> {
address.setCity(addrRequest.getCity());
address.setState(addrRequest.getState());
address.setStreet(addrRequest.getStreet());
address.setPostalCode(addrRequest.getPostalCode());
Person p = new Person();
p.setId(personId);
address.setPerson(p);
return repository.save(address);
}).orElseThrow(() -> new ResourceNotFoundException("address id not found.."));
}
}

Answer 1

Most likely repository.save(address) returns null. You are mocking the method, but only for the argument equal addr1. Inside the AddressService a different instanceof the address is created. I'm guessing that Address class does not implement equals method (or includes the person field in the implementation), so when(repository.save(addr1)).thenReturn(addr1) does not match the call and null is returned.
To solve the problem try using Mockito.doAnswer instead of the Mockito.when:
Mockito.doAnswer(invocation -> invocation.getArguments()[0]).when(repo).save(Mockito.any(Address.class));