Using jUnit mock objects with Spring - spring

Question

I'm trying to write a unit test for a class that uses Spring. The code itself seems to be fine, but I keep getting a null pointer exception on my When statements for some reason. The source code is as follows:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(locations = {"/spring-bean-config.xml"}
public class testClass {
#Mock TestPerson mockTestPerson;
private TestObject testObject;
#Before
public void setup() { testObject = new TestObject(); }
#Test
public void testGetFullName() throws Exception {
String firstname = "Bob";
String lastname = "Barker";
when(testPerson.getFirstName()).thenReturn(firstName); // Throws NullPointerException
when(testPerson.getLastName()).thenReturn(lastName); // I suspect this guy will do the same.
String result = testObject.getFullName(mockTestPerson);
assertNotNull(result);
}
}
The TestPerson class is pretty simple:
public class testPerson {
private String firstName;
private String lastName;
public String getFirstName() {
return this.firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName {
return this.LastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}
And finally, the TestObject class.
public class TestObject {
public String getFullName(TestPerson testPerson) {
return testPerson.getFirstName + " " + testPerson.getLastName();
}
}
Simple, yes? To be honest, it might be easier to just initialize a TestPerson object from within the test. For argument's sake (and for the fact that my other projects that NEED to use #Mock tend to make the same complaints), I need to know how to properly mock object using the #Mock annotation AND SpringJUnit4ClassRunner.
EDIT:
So I tried creating a new TestPerson from directly within the test and setting the first and last name. Curiously, I still get a null pointer exception at the same line. Why is that? If I can't create or mock the object, then how do I verify the object is working?

Answer 1

Your test doesn't need Spring. You should remove the both annotations
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(locations = {"/spring-bean-config.xml"}
The #Mock annotation is not doing anything by itself. You have to create the mocks. This can be done using a rule
#Rule
public MockitoRule rule = MockitoJUnit.rule();
or by an #Before method.
#Before
public void initMocks() {
MockitoAnnotations.initMocks(this);
}
See the Mockito documentation for details.