  @Test
  public void should_throw_an_illegal_state_exception_as_the_identifiersToExclude_parameter_is_not_valid() {

    try {
      ExperimentalIdentifierCheck check = new ExperimentalIdentifierCheck();
      check.setIdentifiersToExclude("(");
      CssCheckVerifier.issuesOnCssFile(check, getTestFile("experimentalIdentifierUsage.css")).noMore();
    } catch (IllegalStateException e) {
      assertThat(e.getMessage()).isEqualTo("Check css:experimental-identifier-usage (Experimental identifiers should not be used): "
        + "identifiersToExclude parameter \"(\" is not a valid regular expression.");
    }
  }