instance method environment

# File activesupport/lib/active_support/testing/performance.rb, line 200
        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