@Test(expectedExceptions = ClassNotFoundException.class)
public void testFindFirstOfShouldThrowClassNotFoundExceptionWhenNoClassIsFound() throws ClassNotFoundException {

    //GIVEN
    Set<Class<? extends Object>> value = new HashSet<>();
    given(packageBasedClassFinderCore.find(PACKAGE_NAME, INTERFACE_OR_CLASS)).willReturn(value);
    //WHEN
    underTest.findFirstOf(INTERFACE_OR_CLASS, PACKAGE_NAME);
    //THEN exception is thrown
}