    # File lib/active_support/testing/performance.rb, line 125
            def environment
              unless defined? @env
                app = "#{$1}.#{$2}" if File.directory?('.git') && `git branch -v` =~ /^\* (\S+)\s+(\S+)/

                rails = Rails::VERSION::STRING
                if File.directory?('vendor/rails/.git')
                  Dir.chdir('vendor/rails') do
                    rails += ".#{$1}.#{$2}" if `git branch -v` =~ /^\* (\S+)\s+(\S+)/
                  end
                end

                ruby = defined?(RUBY_ENGINE) ? RUBY_ENGINE : 'ruby'
                ruby += "-#{RUBY_VERSION}.#{RUBY_PATCHLEVEL}"

                @env = [app, rails, ruby, RUBY_PLATFORM] * ','
              end

              @env
            end