--- a/test/openssl/test_ssl.rb
+++ b/test/openssl/test_ssl.rb
@@ -67,6 +67,8 @@
         assert_equal @svr_cert.subject, ssl.peer_cert.subject
         assert_equal [@svr_cert.subject, @ca_cert.subject],
           ssl.peer_cert_chain.map(&:subject)
+
+        ssl.puts "abc"; assert_equal "abc\n", ssl.gets
       }
     end
   end
@@ -892,7 +894,9 @@
         }
         start_server(ctx_proc: ctx_proc, ignore_listener_error: true) do |port|
           begin
-            server_connect(port) { }
+            server_connect(port) { |ssl|
+              ssl.puts "abc"; assert_equal "abc\n", ssl.gets
+            }
           rescue OpenSSL::SSL::SSLError, Errno::ECONNRESET
           else
             supported << ver
@@ -950,6 +954,7 @@
           if ver == cver
             server_connect(port, ctx1) { |ssl|
               assert_equal vmap[cver][:name], ssl.ssl_version
+              ssl.puts "abc"; assert_equal "abc\n", ssl.gets
             }
           else
             assert_handshake_error { server_connect(port, ctx1) { } }
@@ -963,6 +968,7 @@
             if ver == cver
               server_connect(port, ctx2) { |ssl|
                 assert_equal vmap[cver][:name], ssl.ssl_version
+                ssl.puts "abc"; assert_equal "abc\n", ssl.gets
               }
             else
               assert_handshake_error { server_connect(port, ctx2) { } }
@@ -975,6 +981,7 @@
         ctx3.min_version = ctx3.max_version = nil
         server_connect(port, ctx3) { |ssl|
           assert_equal vmap[ver][:name], ssl.ssl_version
+          ssl.puts "abc"; assert_equal "abc\n", ssl.gets
         }
       }
     end
@@ -993,6 +1000,7 @@
         ctx1.min_version = cver
         server_connect(port, ctx1) { |ssl|
           assert_equal vmap[supported.last][:name], ssl.ssl_version
+          ssl.puts "abc"; assert_equal "abc\n", ssl.gets
         }
 
         # Client sets max_version
@@ -1001,6 +1009,7 @@
         if cver >= sver
           server_connect(port, ctx2) { |ssl|
             assert_equal vmap[cver][:name], ssl.ssl_version
+            ssl.puts "abc"; assert_equal "abc\n", ssl.gets
           }
         else
           assert_handshake_error { server_connect(port, ctx2) { } }
@@ -1019,6 +1028,7 @@
         if cver <= sver
           server_connect(port, ctx1) { |ssl|
             assert_equal vmap[sver][:name], ssl.ssl_version
+            ssl.puts "abc"; assert_equal "abc\n", ssl.gets
           }
         else
           assert_handshake_error { server_connect(port, ctx1) { } }
@@ -1033,6 +1043,7 @@
           else
             assert_equal vmap[cver][:name], ssl.ssl_version
           end
+          ssl.puts "abc"; assert_equal "abc\n", ssl.gets
         }
       end
     }