anchor.diff:  [source,java]
   ----
   ConstraintViolation<Customer> violation = ...;
  -
  -assertThat( violation.getPropertyPath.toString() ).isEqualTo( "revenuePerYearAndCategory[(2015,cds)].<table cell>" );
   
   Iterator<Node> path = violation.getPropertyPath().iterator();
   
  
positive.code: 
  assertThat( path.hasNext() ).isFalse();
  ----
  
negative.code: 		this.columnKey = columnKey;
  	}
  
  	// equals(), hashCode() ...
  }
  ----
  