How to mock a MyBatis mapper method using JMockit - jmockit

Question

We have a service component (#service) which internally uses MyBatis to do CRUD operations. All the components are managed by Spring.
Lets assume our MyBatis mapper file
class MyBatisMapper{
public void getData(Map<String,Object> arg);
}
In our mybatis xml file,we have element defined for a callable statement. arg is a map which holds IN and OUT parameters.
Our service component is like
#Service("myService")
class MyService{
#Autowired
private MyBatisMapper myMapper;
public void processData(){
Map<String,Object> input = new HashMap<String,Object>();
............
............
myMapper.getDat(input);
Object response = input.get("RESPONSE");
//process response and so on
}
My objective is to write Junits for the service component and don't have to interact with DB. So, I tried to use JMockIt to mock some of the DAO operations
My attempt is ike
#Mocked
#Injectable
private MyBatisMapper myMapper;
#Test
public void testService() {
new NonStrictExpectations(){
{
Map<String,Object> input = new HashMap<String,Object>();
input.put("xxx,"yyy");
myMapper.getData(input);
}
};
}
But when I ran my tests, I noticed that call went through actualy DB , instead of mocked one.
How to make sure only the mocked components gets called, instead of the actual object

Answer 1

#Injectable mock instances only get injected into #Tested objects. And to specify a return value from a mocked method, you need to assign it to the result field. So, the test should look like the following:
#Tested MyService myService;
#Injectable MyBatisMapper myMapper;
#Test
public void testService() {
final Map<String,Object> data = new HashMap<String, Object>();
data.put("RESPONSE", "yyy");
new Expectations() {{
myMapper.getData((Map<String, Object>) any); result = data;
}};
myService.processData();
// Assert some expected outcome.
}

Answer 2

Thank you Rogerio. I tried to follow the approach you mentioned, but still I see the call going to the actual object. There is a point which I did not mention earlier. My project is spring based and the components are all autowired.
My test has
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(locations = {"classpath:spring/test-applicationContext.xml"})
and test-applicationContext.xml has component scan. So I think, Spring is injecting the actual object ignoring the mock instruction.
Am I wrong ?