protected final void assertDoesNotHaveDuplicates ( ) { isNotNull ( ) ; Collection < ? > duplicates = duplicatesFrom ( actualAsList ( ) ) ; if ( duplicates . isEmpty ( ) ) { return ; } failIfCustomMessageIsSet ( ) ; throw failure ( format ( "<%s> contains duplicate(s):<%s>" , actual , duplicates ) ) ; }
Verifies that the actual group of objects does not have duplicates .