public RollbackRule(String exceptionName) {
        if (StringUtils.isNullOrEmpty(exceptionName)) {
            throw new IllegalArgumentException("'exceptionName' cannot be null or empty");
        }
        this.exceptionName = exceptionName;
    }
@Test
    public void RollbackRule() {
        RollbackRule rr = new RollbackRule(Exception.class);
        assertThat(rr.getDepth(new Exception())).isEqualTo(0);
    }