MockMethod注解无法生效

无法mock，在调用AgentIServiceImpl类的 getAvailableAgentCount方法时，agentMapper一直报空指针的错。
测试类：

public class AgentIServiceImplTest {

private AgentIServiceImpl agentIService = new AgentIServiceImpl();

public static class Mock {
@MockMethod(targetClass = AgentIServiceImpl.class)
public int getAvailableCount() {
System.out.println("mock生效");
return 1;
}

@MockMethod(targetClass = AgentIServiceImpl.class)
public Map getAvailableRegionCount() {
System.out.println("mock生效");
return new HashMap<>();
}
}

@Test
public void testGetAvailableCount() {
Map res = agentIService.getAvailableRegionCount();
assertNotNull(res);
//int count = agentIService.getAvailableAgentCount();
//assertEquals(1, count);
}
}

源类：
public class AgentIServiceImpl extends ServiceImpl implements AgentIService {

@Resource
private AgentMapper agentMapper;

@Override
public int getAvailableCount() {
return agentMapper.getAvailableAgentCount();
}

@Override
public Map getAvailableRegionCount() {
return agentMapper.queryAgentRegionCount();
}

}

Start with AgentIServiceImplTest and the AgentIServiceImpl methods getAvailableCount and getAvailableRegionCount, then inspect how @MockMethod is discovered and applied. Run testGetAvailableCount and compare the annotated Mock methods with the invoked service methods; done means the mock is applied and the test no longer fails because agentMapper is null.

Written by the indexing model from the issue text.