testFilter.scala

      def ignoreSomeLinesMatcher[L1 : LinesContent, L2 : LinesContent](): LinesPairComparisonMatcher[L1, L2] = LinesPairComparisonMatcher[L1, L2](
          filter = new DifferenceFilter() {
                     def apply(diffs: (Seq[_], Seq[_])) = {
                       throw new Exception("OK!")
                     }
                   }
      )

      rootGeneratedPromisesDir must haveSameFilesAs(new File(EXPECTED_SHARE, "root")).withMatcher(ignoreSomeLinesMatcher())