diff --git a/async-websocket.gemspec b/async-websocket.gemspec
index 23331ad..ff23c82 100644
--- a/async-websocket.gemspec
+++ b/async-websocket.gemspec
@@ -24,6 +24,6 @@ Gem::Specification.new do |spec|
 	
 	spec.add_development_dependency "bundler"
 	spec.add_development_dependency "covered"
-	spec.add_development_dependency "sus", "~> 0.16.0"
+	spec.add_development_dependency "sus", "~> 0.18"
 	spec.add_development_dependency "sus-fixtures-async-http", "~> 0.2.3"
 end
diff --git a/gems.rb b/gems.rb
index 6eac629..bc04589 100644
--- a/gems.rb
+++ b/gems.rb
@@ -19,4 +19,4 @@
 	gem "bake-test-external"
 end
 
-gem "rack", "~> 3.0.0"
+# gem "protocol-websocket", path: "../protocol-websocket"
diff --git a/lib/async/websocket/client.rb b/lib/async/websocket/client.rb
index 4472762..e21339a 100644
--- a/lib/async/websocket/client.rb
+++ b/lib/async/websocket/client.rb
@@ -41,8 +41,8 @@ def initialize(client, connection)
 					super(connection)
 				end
 				
-				def close
-					super
+				def close(...)
+					super(...)
 					
 					if @client
 						@client.close
diff --git a/lib/async/websocket/version.rb b/lib/async/websocket/version.rb
index 9f41810..dda41ad 100644
--- a/lib/async/websocket/version.rb
+++ b/lib/async/websocket/version.rb
@@ -5,6 +5,6 @@
 
 module Async
 	module WebSocket
-		VERSION = "0.24.0"
+		VERSION = "0.25.0"
 	end
 end
diff --git a/test/async/websocket/client.rb b/test/async/websocket/client.rb
index 7b70c64..ae71654 100644
--- a/test/async/websocket/client.rb
+++ b/test/async/websocket/client.rb
@@ -20,16 +20,73 @@
 		end
 	end
 	
-	it "can connect to a websocket server and close underlying client" do
-		Async do |task|
+	with '#send_close' do
+		it "can read incoming messages and then close" do
+			connection = Async::WebSocket::Client.connect(client_endpoint)
+			3.times do
+				connection.send_text("Hello World!")
+			end
+			
+			# This informs the server we are done echoing messages:
+			connection.send_close
+			
+			# Collect all the echoed messages:
+			messages = []
+			while message = connection.read
+				messages << message
+			end
+			
+			expect(messages.size).to be == 3
+			expect(connection).to be(:closed?)
+		ensure
+			connection&.close
+		end
+	end
+	
+	with '#close' do
+		it "can connect to a websocket server and close underlying client" do
+			Async do |task|
+				connection = Async::WebSocket::Client.connect(client_endpoint)
+				connection.send_text("Hello World!")
+				message = connection.read
+				expect(message.to_str).to be == "Hello World!"
+				
+				connection.close
+				expect(task.children).to be(:empty?)
+			end.wait
+		end
+		
+		it "can connect to a websocket server and close underlying client with an error code" do
+			Async do |task|
+				connection = Async::WebSocket::Client.connect(client_endpoint)
+				connection.send_text("Hello World!")
+				message = connection.read
+				expect(message.to_str).to be == "Hello World!"
+				
+				connection.close(Protocol::WebSocket::Error::GOING_AWAY, "Bye!")
+				expect(task.children).to be(:empty?)
+			end.wait
+		end
+	end
+	
+	with "#close(1001)" do
+		let(:app) do
+			Protocol::HTTP::Middleware.for do |request|
+				Async::WebSocket::Adapters::HTTP.open(request) do |connection|
+					connection.send_text("Hello World!")
+					connection.close(1001)
+				end
+			end
+		end
+
+		it 'closes with custom error' do
 			connection = Async::WebSocket::Client.connect(client_endpoint)
-			connection.send_text("Hello World!")
 			message = connection.read
-			expect(message.to_str).to be == "Hello World!"
 			
-			connection.close
-			expect(task.children).to be(:empty?)
-		end.wait
+			expect do
+				connection.read
+			end.to raise_exception(Protocol::WebSocket::Error).and(have_attributes(code: be == 1001))
+		end
 	end
 	
 	with 'missing support for websockets' do