Mockito not mocking my #Autowired class - spring

Question

I came across a problem, while mocking my class i get NullPointerException on mocked object and I cant figure out why mockito is not mocking only one class annotated by #Mock. Do someone have any idea what's the problem there ?
Tested class :
public class TimeoutJpaTransactionManager extends JpaTransactionManager {
private final String TRANSACTION_METHOD_NAME= String.join(".", ZapisPakietuReceptService.class.getName(), "transactionMethod");
#Autowired
private TransactionTimeoutConfig transactionTimeoutConfig;
public TimeoutJpaTransactionManager(EntityManagerFactory emf) {
super(emf);
}
protected int determineTimeout(TransactionDefinition definition) {
if (TRANSACTION_METHOD_NAME.equals(definition.getName())) {
return transactionTimeoutConfig.getSgr();
}
return super.getDefaultTimeout();
}
}
Autowired class :
#Getter
#Setter
#Component
#ConfigurationProperties(prefix = "transaction.timeout")
public class TransactionTimeoutConfig {
private int sgr;
}
Test class:
public class TimeoutJpaTransactionManagerTest {
#InjectMocks
private TimeoutJpaTransactionManager timeoutJpaTransactionManager;
#Mock
private EntityManagerFactory entityManagerFactory;
#Mock
private TransactionDefinition transactionDefinition;
#Mock
private TransactionTimeoutConfig transactionTimeoutConfig;
private final String TRANSACTION_METHOD_NAME_MOCK= String.join(".", ZapisPakietuReceptService.class.getName(), "transactionMethod");
private final int TIMEOUT_VALUE= 30;
#BeforeMethod
public void setUp() {
MockitoAnnotations.initMocks(this);
}
#Test
public void testDetermineTimeout() {
//given
Mockito.when(transactionDefinition.getName()).thenReturn(TRANSACTION_METHOD_NAME_MOCK);
Mockito.when(transactionTimeoutConfig.getSgr()).thenReturn(TIMEOUT_VALUE);
//when
int result = timeoutJpaTransactionManager.determineTimeout(transactionDefinition);
//then
Assertions.assertThat(result).isEqualTo(TIMEOUT_VALUE);
}
}
Whats weird and i cant undestand is that by adding another line like that all seems to work and TransactionDefinition is really mocked :
#BeforeMethod
public void setUp() {
MockitoAnnotations.initMocks(this);
MockitoAnnotations.initMocks(this);
}

Answer 1

Thanks to the M. Deinum comment i was able to figure it out, it seems the problem was with mixing field and constructor injections. Solution is to either move dependencies to the constructor and then wire it there or modify the current test case to
#InjectMocks
private TimeoutJpaTransactionManager timeoutJpaTransactionManager;
#Mock
private TransactionDefinition transactionDefinition;
#Mock
private TransactionTimeoutConfig transactionTimeoutConfig;
private EntityManagerFactory entityManagerFactory;
private final String TRANSACTION_METHOD_NAME_MOCK= String.join(".", ZapisPakietuReceptService.class.getName(), "transactionMethod");
private final int TIMEOUT_VALUE= 30;
#BeforeMethod
public void setUp() {
entityManagerFactory = Mockito.mock(EntityManagerFactory.class);
timeoutJpaTransactionManager = new TimeoutJpaTransactionManager(entityManagerFactory);
MockitoAnnotations.initMocks(this);
}