code: @Test public void should_fail_if_actual_contains_duplicates_according_to_custom_comparison_strategy(){
    AssertionInfo info=someInfo();
    Collection<String> duplicates=newLinkedHashSet("LUKE","yoda");
    actual.addAll(duplicates);
    try {
      iterablesWithCaseInsensitiveComparisonStrategy.assertDoesNotHaveDuplicates(info,actual);
    }
   catch (  AssertionError e) {
      verify(failures).failure(info,shouldNotHaveDuplicates(actual,duplicates,comparisonStrategy));
      return;
    }
    failBecauseExpectedAssertionErrorWasNotThrown();
  }
  