diff --git a/ffi/Gemfile b/ffi/Gemfile
index 2a76178..b06b864 100644
--- a/ffi/Gemfile
+++ b/ffi/Gemfile
@@ -9,6 +9,5 @@ group :development do
 end
 
 group :test do
-  gem "async-io"
   gem "rspec"
 end
diff --git a/mri/Gemfile b/mri/Gemfile
index 2a76178..b06b864 100644
--- a/mri/Gemfile
+++ b/mri/Gemfile
@@ -9,6 +9,5 @@ group :development do
 end
 
 group :test do
-  gem "async-io"
   gem "rspec"
 end
diff --git a/spec/acceptance/server_spec.rb b/spec/acceptance/server_spec.rb
deleted file mode 100644
index 56192dd..0000000
--- a/spec/acceptance/server_spec.rb
+++ /dev/null
@@ -1,32 +0,0 @@
-# frozen_string_literal: true
-
-require "timeout"
-require "async/io"
-require "llhttp"
-
-require_relative "support/server"
-
-RSpec.describe "parsing in context of a server" do
-  before do
-    @pid = Process.fork {
-      endpoint = Async::IO::Endpoint.tcp("0.0.0.0", 9000)
-
-      Async do
-        Server.new(endpoint).run
-
-        parser = LLHttp::Parser.new(LLHttp::Delegate.new, type: :request)
-        parser.parse("GET / HTTP/1.1\r\n")
-      end
-    }
-  end
-
-  after do
-    Process.kill("HUP", @pid)
-  end
-
-  it "parses" do
-    Timeout.timeout(1) do
-      expect(system("curl -v http://localhost:9000")).to be(true)
-    end
-  end
-end
diff --git a/spec/acceptance/support/server.rb b/spec/acceptance/support/server.rb
deleted file mode 100644
index 10de381..0000000
--- a/spec/acceptance/support/server.rb
+++ /dev/null
@@ -1,64 +0,0 @@
-# frozen_string_literal: true
-
-require "async/io"
-require "async/io/stream"
-
-class Delegate < LLHttp::Delegate
-  def initialize
-    @finished_headers = false
-  end
-
-  def finished_headers?
-    @finished_headers == true
-  end
-
-  def on_headers_complete
-    @finished_headers = true
-  end
-
-  def reset
-    @finished_headers = false
-  end
-end
-
-class Server
-  CRLF = "\r\n"
-
-  def initialize(endpoint)
-    @endpoint = endpoint
-    @delegate = Delegate.new
-    @parser = LLHttp::Parser.new(@delegate, type: :request)
-  end
-
-  def run
-    @endpoint.accept(&method(:accept))
-  end
-
-  private def accept(client, address, task:)
-    stream = Async::IO::Stream.new(client, sync: false)
-
-    while parse_next(stream)
-      stream.write("HTTP/1.1 204 No Content\r\n")
-      stream.write("content-length: 0\r\n\r\n")
-      stream.flush
-
-      @delegate.reset
-
-      task.yield
-    end
-  ensure
-    stream.close
-
-    @parser.reset
-  end
-
-  private def parse_next(stream)
-    while (line = stream.read_until(CRLF, chomp: false))
-      @parser << line
-
-      if @delegate.finished_headers?
-        return true
-      end
-    end
-  end
-end