code: public static void doesNotContain(String textToSearch, String substring, String message) {
          if (StringUtils.hasLength(textToSearch) && StringUtils.hasLength(substring) &&
              textToSearch.contains(substring)) {
              throw new IllegalArgumentException(message);
          }
      }
docs: Assert that the given text does not contain the given substring. <pre class="code">Assert .doesNotContain(name,
  "rod", "Name must not contain 'rod'");</pre>
  
  @param textToSearch the text to search.
  @param substring the substring to find within the text.
  @param message the exception message to use if the assertion fails.
  
  @throws IllegalArgumentException if the text contains the substring.