Use Rackup::Server with Rack v3

Author: orien

Gemfile

@@ -8,7 +8,9 @@ group :development do
 end
 
 group :test do
-  gem 'rack', "~> #{ENV["RACK_VERSION"] || "3"}"
+  rack_version = ENV.fetch('RACK_VERSION', '3')
+  gem 'rack', "~> #{rack_version}"
+  gem 'rackup' if rack_version == '3'
   gem 'rack-test', '~> 2'
   gem 'rspec', '~> 3.0', '>= 3.6.0'
   gem 'rspec-its', '~> 1.2'

lib/webmachine/adapters/rack.rb

@@ -52,7 +52,12 @@ def run
           Host: application.configuration.ip
         }).merge(application.configuration.adapter_options)
 
-        @server = ::Rack::Server.new(options)
+        if ::Rack::RELEASE.start_with?('3.')
+          require 'rackup'
+          @server = ::Rackup::Server.new(options)
+        else
+          @server = ::Rack::Server.new(options)
+        end
         @server.start
       end