public RuleDto setRuleKey(String ruleKey) {
    checkArgument(ruleKey.length() <= 200, "Rule key is too long: %s", ruleKey);
    this.ruleKey = ruleKey;
    return this;
  }
@Test
  void setRuleKey_whenTooLong_shouldFail() {
    assertThatThrownBy(() -> new RuleDto().setRuleKey(repeat("x", 250)))
      .isInstanceOf(IllegalArgumentException.class)
      .hasMessageContaining("Rule key is too long: ");
  }