Question

I am trying to write a Unit test for a class that has several of its fields marked @Autowired. Given the fact that Spring is automatically resolving the concrete implementations for these fields, I am having a hard time figuring out how to plug my Mock objects(created via EasyMock) as the dependencies during the test-run. Using @Autowired in the class means lack of setters in that class. Is there a way for me to plug my mock objects in without creating additional setters in class?

Here’s an example of what I am trying to accomplish:

public class SomeClassUnderTest implements SomeOtherClass {
    
    @Autowired
    private SomeType someType;
    
    @Autowired
    private SomeOtherType someOtherType;
    
    @Override
    public SomeReturnType someMethodIWouldLikeToTest(){
    //Uses someType and someOtherType and returns SomeReturnType
    }
    
}

Here’s how I am crafting my Test class before I hit the wall:

public class MyTestClassForSomeClassUnderTest{
  private SomeType someType;
  private SomeOtherType someOtherType;
  
  @Before
  public void testSetUp(){
    SomeClassUnderTest someClassToTest = new SomeClassUnderTest();
    someType = EasyMock.createMock(SomeType.class);
    someOtherType = EasyMock.createMock(SomeOtherType.class);
    //How to set dependencies????
  }

  @Test
  public void TestSomeMethodIWouldLikeToTest(){
    //??????
  } 

}

It will be great to get a push in the right direction.

Thanks

Answer 1

You can reflectively inject dependencies directly into the field using ReflectionTestUtils, e.g.

ReflectionTestUtils.setField( testInstance, "fieldName", fieldValue );

Some would argue that it’s preferable to add a package-visible setter method to the class anyway, used solely by the tests. Alternatively, use autowired constructors, rather than autowired fields, and inject the test dependencies into that.