DateTimeConverter Unit test cases

Can Anyone help me to write unit test cases for this method?

@Override
public Property resolveProperty(Type type, ModelConverterContext context, Annotation[] annotations, Iterator<ModelConverter> chain) {
  final JavaType jType = Json.mapper().constructType(type);
  if (jType != null) {
    final Class<?> cls = jType.getRawClass();
    if (Date.class.isAssignableFrom(cls)) {
      //DateTimeProperty property =
      //        (DateTimeProperty) chain.next().resolveProperty(type, context, annotations, chain);
      return new LongProperty();
    }
  }
  return chain.hasNext() ?
      chain.next().resolveProperty(type, context, annotations, chain)
      : null;
}

I have tried like this but its not working, dont know what i am missing

@Test
    public void testResolveProperty() {
        Type type1 = SwaggerDateTimeConverter.class;
        type1=Mockito.mock(Type.class);
        javaType = Mockito.mock(JavaType.class);
        //javaType = Json.mapper().constructType(type1);
        Class<?> cls = javaType.getRawClass();
//        cls=Mockito.mock(Class.class);
        Mockito.when(json.mapper().constructType(type1)).thenReturn(javaType);
        assertNotNull(javaType);
        assertSame(JavaType.class,javaType.getRawClass());
        assertTrue(Date.class.isAssignableFrom(cls));
       assertSame(longProperty,swaggerDateTimeConverter.resolveProperty(type1,context, type1.getAnnotations(), chain));


        }