# File lib/rspec/expectations/differ.rb, line 82
      def color_diff(diff)
        return diff unless RSpec::Matchers.configuration.color?

        diff.lines.map { |line|
          case line[0].chr
          when "+"
            green line
          when "-"
            red line
          when "@"
            line[1].chr == "@" ? blue(line) : line
          else
            line
          end
        }.join
      end