add connection pool keepalive test

Author: azrle

Vagrantfile

@@ -2,6 +2,11 @@ VAGRANTFILE_API_VERSION = "2"
 
 Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
   config.vm.box = 'hashicorp/precise64'
+  config.vm.provision "shell", inline: <<-SHELL
+  echo 'ClientAliveInterval 1' >> /etc/ssh/sshd_config
+  echo 'ClientAliveCountMax 1' >> /etc/ssh/sshd_config
+  service ssh restart
+  SHELL
 
   json_config_path = File.join("test", "boxes.json")
   list = File.open(json_config_path).read

test/functional/backends/test_netssh.rb

@@ -212,6 +212,20 @@ def test_interaction_handler
         end.run
         assert_equal("Enter Data\nCaptured SOME DATA", captured_command_result)
       end
+
+      def test_connection_pool_keepalive
+        # ensure we enable connection pool
+        SSHKit::Backend::Netssh.pool.idle_timeout = 10
+        Netssh.new(a_host) do |_host|
+          test :false
+        end.run
+        sleep 2.5
+        captured_command_result = nil
+        Netssh.new(a_host) do |_host|
+          captured_command_result = capture(:echo, 'some_value')
+        end.run
+        assert_equal "some_value", captured_command_result
+      end
     end
 
   end