diff --git a/library/socket/tcpsocket/initialize_spec.rb b/library/socket/tcpsocket/initialize_spec.rb
index a3cee05412..7d546ad69c 100644
--- a/library/socket/tcpsocket/initialize_spec.rb
+++ b/library/socket/tcpsocket/initialize_spec.rb
@@ -7,6 +7,12 @@
       it 'raises Errno::ECONNREFUSED' do
         -> { TCPSocket.new(ip_address, 666) }.should raise_error(Errno::ECONNREFUSED)
       end
+
+      it 'raises Errno::ETIMEDOUT with :connect_timeout' do
+        -> {
+          TCPSocket.new("192.0.2.1", 80, connect_timeout: 0)
+        }.should raise_error(Errno::ETIMEDOUT)
+      end
     end
 
     describe 'when a server is listening on the given address' do