Use Puma::Server directly so signal handlers aren't overridden

lib/capybara.rb

@@ -439,7 +439,22 @@ end
 
 Capybara.register_server :puma do |app, port, host, **options|
   require 'rack/handler/puma'
-  Rack::Handler::Puma.run(app, { Host: host, Port: port, Threads: "0:4", workers: 0, daemon: false }.merge(options))
+  # If we just run the Puma Rack handler it installs signal handlers which prevent us from being able to interrupt tests.
+  # Therefore construct and run the Server instance ourselves.
+  # Rack::Handler::Puma.run(app, { Host: host, Port: port, Threads: "0:4", workers: 0, daemon: false }.merge(options))
+
+  conf = Rack::Handler::Puma.config(app, { Host: host, Port: port, Threads: "0:4", workers: 0, daemon: false }.merge(options))
+  events = conf.options[:Silent] ? ::Puma::Events.strings : ::Puma::Events.stdio
+
+  events.log "Capybara starting Puma..."
+  events.log "* Version #{Puma::Const::PUMA_VERSION} , codename: #{Puma::Const::CODE_NAME}"
+  events.log "* Min threads: #{conf.options[:min_threads]}, max threads: #{conf.options[:max_threads]}"
+
+  Puma::Server.new(conf.app, events, conf.options).tap do |s|
+    s.binder.parse conf.options[:binds], s.events
+    s.min_threads = conf.options[:min_threads]
+    s.max_threads = conf.options[:max_threads]
+  end.run.join
 end
 
 Capybara.configure do |config|

spec/capybara_spec.rb

@@ -56,27 +56,11 @@ RSpec.describe Capybara do
     end
 
     it "should have :webrick registered" do
-      require 'rack/handler/webrick'
-      mock_app = double('app')
-      Capybara.server = :webrick
-      expect(Rack::Handler::WEBrick).to receive(:run)
-      Capybara.server.call(mock_app, 8000)
+      expect(Capybara.servers[:webrick]).not_to be_nil
     end
 
     it "should have :puma registered" do
-      require 'rack/handler/puma'
-      mock_app = double('app')
-      Capybara.server = :puma
-      expect(Rack::Handler::Puma).to receive(:run).with(mock_app, hash_including(Host: nil, Port: 8000))
-      Capybara.server.call(mock_app, 8000)
-    end
-
-    it "should pass options to server" do
-      require 'rack/handler/puma'
-      mock_app = double('app')
-      Capybara.server = :puma, { Silent: true }
-      expect(Rack::Handler::Puma).to receive(:run).with(mock_app, hash_including(Host: nil, Port: 9000, Silent: true))
-      Capybara.server.call(mock_app, 9000)
+      expect(Capybara.servers[:puma]).not_to be_nil
     end
   end