@Test
public void shouldThrowExceptionIfhereIsAlreadyValueRegisteredUnderTheSameKey() {

    // given
    DefaultContext context = new DefaultContext();
    context.with("TEST", "B");
    // when, cant use CatchException cos context uses static fields
    try {
        context.with("TEST", "A");
        fail();
    }
    catch(DuplicateContextItemException exception) {
        // then success
    }
}