instance method environment

# File activesupport/lib/active_support/testing/performance.rb, line 126
          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