Add tests for the ssh session portion

[belak]

Currently there aren't many tests. It would be nice to have some so we can get tests for functionality.

[progrium]

How's test coverage for you now?

[belak]

Getting there :)

% gocov test | gocov report
ok  	github.com/gliderlabs/ssh	1.225s	coverage: 56.7% of statements

github.com/gliderlabs/ssh/session.go	 session.Exit			 100.00% (10/10)
github.com/gliderlabs/ssh/server.go	 Server.trackListener		 100.00% (9/9)
github.com/gliderlabs/ssh/context.go	 sshContext.applyConnMetadata	 100.00% (8/8)
github.com/gliderlabs/ssh/server.go	 Server.Close			 100.00% (8/8)
github.com/gliderlabs/ssh/server.go	 Server.trackConn		 100.00% (7/7)
github.com/gliderlabs/ssh/context.go	 newContext			 100.00% (6/6)
github.com/gliderlabs/ssh/session.go	 session.Signals		 100.00% (5/5)
github.com/gliderlabs/ssh/conn.go	 serverConn.Read		 100.00% (5/5)
github.com/gliderlabs/ssh/server.go	 @74:29				 100.00% (4/4)
github.com/gliderlabs/ssh/conn.go	 serverConn.Close		 100.00% (4/4)
github.com/gliderlabs/ssh/tcpip.go	 @48:5				 100.00% (3/3)
github.com/gliderlabs/ssh/tcpip.go	 @53:5				 100.00% (3/3)
github.com/gliderlabs/ssh/server.go	 Server.closeDoneChanLocked	 100.00% (3/3)
github.com/gliderlabs/ssh/server.go	 Server.getDoneChan		 100.00% (3/3)
github.com/gliderlabs/ssh/server.go	 Server.getDoneChanLocked	 100.00% (3/3)
github.com/gliderlabs/ssh/options.go	 @7:9				 100.00% (2/2)
github.com/gliderlabs/ssh/session.go	 session.Permissions		 100.00% (2/2)
github.com/gliderlabs/ssh/session.go	 @196:6				 100.00% (2/2)
github.com/gliderlabs/ssh/session.go	 @218:7				 100.00% (2/2)
github.com/gliderlabs/ssh/options.go	 @68:9				 100.00% (2/2)
github.com/gliderlabs/ssh/options.go	 WrapConn			 100.00% (1/1)
github.com/gliderlabs/ssh/options.go	 PasswordAuth			 100.00% (1/1)
github.com/gliderlabs/ssh/session.go	 session.Context		 100.00% (1/1)
github.com/gliderlabs/ssh/context.go	 sshContext.User		 100.00% (1/1)
github.com/gliderlabs/ssh/context.go	 sshContext.SetValue		 100.00% (1/1)
github.com/gliderlabs/ssh/server.go	 Server.SetOption		 100.00% (1/1)
github.com/gliderlabs/ssh/context.go	 sshContext.Permissions		 100.00% (1/1)
github.com/gliderlabs/ssh/session.go	 @263:10			 100.00% (1/1)
github.com/gliderlabs/ssh/session.go	 session.User			 100.00% (1/1)
github.com/gliderlabs/ssh/server.go	 Server.Shutdown		 92.86% (13/14)
github.com/gliderlabs/ssh/server.go	 Server.config			 84.62% (11/13)
github.com/gliderlabs/ssh/server.go	 Server.ensureHostSigner	 83.33% (5/6)
github.com/gliderlabs/ssh/server.go	 Server.closeListenersLocked	 83.33% (5/6)
github.com/gliderlabs/ssh/server.go	 Server.handleConn		 80.00% (20/25)
github.com/gliderlabs/ssh/conn.go	 serverConn.Write		 80.00% (4/5)
github.com/gliderlabs/ssh/session.go	 sessionHandler			 80.00% (4/5)
github.com/gliderlabs/ssh/util.go	 parseString			 77.78% (7/9)
github.com/gliderlabs/ssh/util.go	 generateSigner			 75.00% (3/4)
github.com/gliderlabs/ssh/tcpip.go	 directTcpipHandler		 70.00% (14/20)
github.com/gliderlabs/ssh/util.go	 parsePtyRequest		 66.67% (10/15)
github.com/gliderlabs/ssh/util.go	 parseWinchRequest		 66.67% (8/12)
github.com/gliderlabs/ssh/util.go	 parseUint32			 66.67% (2/3)
github.com/gliderlabs/ssh/session.go	 session.Pty			 66.67% (2/3)
github.com/gliderlabs/ssh/session.go	 session.handleRequests		 58.49% (31/53)
github.com/gliderlabs/ssh/server.go	 Server.Serve			 52.17% (12/23)
github.com/gliderlabs/ssh/ssh.go	 KeysEqual			 40.00% (2/5)
github.com/gliderlabs/ssh/conn.go	 serverConn.updateDeadline	 28.57% (2/7)
github.com/gliderlabs/ssh/session.go	 session.Write			 22.22% (2/9)
github.com/gliderlabs/ssh/util.go	 signerFromBlock		 0.00% (0/13)
github.com/gliderlabs/ssh/agent.go	 @58:6				 0.00% (0/11)
github.com/gliderlabs/ssh/options.go	 @24:9				 0.00% (0/9)
github.com/gliderlabs/ssh/util.go	 decodePemBlocks		 0.00% (0/7)
github.com/gliderlabs/ssh/server.go	 Server.ListenAndServe		 0.00% (0/7)
github.com/gliderlabs/ssh/agent.go	 NewAgentListener		 0.00% (0/7)
github.com/gliderlabs/ssh/options.go	 @43:9				 0.00% (0/6)
github.com/gliderlabs/ssh/agent.go	 ForwardAgentConnections	 0.00% (0/6)
github.com/gliderlabs/ssh/ssh.go	 Serve				 0.00% (0/5)
github.com/gliderlabs/ssh/server.go	 @83:30				 0.00% (0/5)
github.com/gliderlabs/ssh/ssh.go	 ListenAndServe			 0.00% (0/5)
github.com/gliderlabs/ssh/session.go	 session.PublicKey		 0.00% (0/4)
github.com/gliderlabs/ssh/agent.go	 @73:7				 0.00% (0/3)
github.com/gliderlabs/ssh/agent.go	 @68:7				 0.00% (0/3)
github.com/gliderlabs/ssh/options.go	 @15:9				 0.00% (0/2)
github.com/gliderlabs/ssh/options.go	 @58:9				 0.00% (0/2)
github.com/gliderlabs/ssh/session.go	 session.Command		 0.00% (0/1)
github.com/gliderlabs/ssh/session.go	 session.RemoteAddr		 0.00% (0/1)
github.com/gliderlabs/ssh/session.go	 session.LocalAddr		 0.00% (0/1)
github.com/gliderlabs/ssh/context.go	 sshContext.SessionID		 0.00% (0/1)
github.com/gliderlabs/ssh/context.go	 sshContext.ClientVersion	 0.00% (0/1)
github.com/gliderlabs/ssh/context.go	 sshContext.ServerVersion	 0.00% (0/1)
github.com/gliderlabs/ssh/context.go	 sshContext.RemoteAddr		 0.00% (0/1)
github.com/gliderlabs/ssh/ssh.go	 Handle				 0.00% (0/1)
github.com/gliderlabs/ssh/context.go	 sshContext.LocalAddr		 0.00% (0/1)
github.com/gliderlabs/ssh/agent.go	 setAgentRequested		 0.00% (0/1)
github.com/gliderlabs/ssh/options.go	 PublicKeyAuth			 0.00% (0/1)
github.com/gliderlabs/ssh/agent.go	 AgentRequested			 0.00% (0/1)
github.com/gliderlabs/ssh/options.go	 @59:21				 0.00% (0/1)
github.com/gliderlabs/ssh/options.go	 HostKeyFile			 0.00% (0/1)
github.com/gliderlabs/ssh/server.go	 Server.AddHostKey		 0.00% (0/1)
github.com/gliderlabs/ssh/wrap.go	 ParsePublicKey			 0.00% (0/1)
github.com/gliderlabs/ssh/server.go	 Server.Handle			 0.00% (0/1)
github.com/gliderlabs/ssh/options.go	 NoPty				 0.00% (0/1)
github.com/gliderlabs/ssh/session.go	 session.Environ		 0.00% (0/1)
github.com/gliderlabs/ssh/wrap.go	 ParseAuthorizedKey		 0.00% (0/1)
github.com/gliderlabs/ssh/options.go	 HostKeyPEM			 0.00% (0/1)
github.com/gliderlabs/ssh		 ----------------------------	 56.73% (257/453)

Total Coverage: 56.73% (257/453)