Fix problems with UnexpectedFrameEnd raise

lib/amqp/client/connection.rb

@@ -443,7 +443,7 @@ def establish(socket, user, password, vhost, options)
 
           type, channel_id, frame_size = buf.unpack("C S> L>")
           frame_end = buf.getbyte(frame_size + 7)
-          raise UnexpectedFrameEnd, frame_end if frame_end != 206
+          raise Error::UnexpectedFrameEnd, frame_end if frame_end != 206
 
           case type
           when 1 # method frame

test/amqp/client_test.rb

@@ -16,6 +16,15 @@ def test_it_can_connect
     assert connection
   end
 
+  def test_it_raises_on_connecting_to_unrelated_service
+    with_fake_server do |port|
+      client = AMQP::Client.new("amqp://guest1:guest2@localhost:#{port}")
+      assert_raises(AMQP::Client::Error) do
+        client.connect
+      end
+    end
+  end
+
   def test_it_raises_on_bad_credentials
     client = AMQP::Client.new("amqp://guest1:guest2@localhost")
     assert_raises(AMQP::Client::Error) do

test/test_helper.rb

@@ -37,5 +37,28 @@ def skip_if_no_sudo
   end
 end
 
+require "socket"
+module FakeServer
+  def with_fake_server(host: "127.0.0.1")
+    server = TCPServer.new(host, 0)
+
+    Thread.new do
+      loop do
+        client = server.accept
+        client.puts "foobar"
+        client.close
+        break
+      rescue IOError
+        break
+      end
+    end
+
+    yield server.connect_address.ip_port
+
+    server.close
+  end
+end
+
 Minitest::Test.prepend TimeoutEveryTestCase
 Minitest::Test.prepend SkipSudoTestCase
+Minitest::Test.prepend FakeServer