# File lib/test/unit/assertions.rb, line 1734
          def max_diff_target_string_size
            return @@max_diff_target_string_size if @@max_diff_target_string_size

            size = ENV["TEST_UNIT_MAX_DIFF_TARGET_STRING_SIZE"]
            if size
              begin
                size = Integer(size)
              rescue ArgumentError
                size = nil
              end
            end
            size || MAX_DIFF_TARGET_STRING_SIZE
          end