main.go

package main

import (
        "bufio"
        "fmt"
        "net"
)

type KVpair struct {
        Key   string
        Value string
}

type Conversation struct {
        Lines []KVpair
}

type Cass struct {
        Address string
}

func (c *Cass) Send(conv Conversation) (string, error) {
        conn, err := net.Dial("tcp", c.Address)
        if err != nil {
                return "", err
        }
        defer conn.Close()

        for _, line := range conv.Lines {
                if _, err := fmt.Fprintf(conn, "%s=%s\n", line.Key, line.Value); err != nil {
                        return "", err
                }
        }

        if _, err := fmt.Fprintln(conn, "END"); err != nil {
                return "", err
        }

        return bufio.NewReader(conn).ReadString('\n')
}

main_test.go

package main

import (
        "bufio"
        "fmt"
        "log"
        "net"
        "os"
        "testing"
)

func TestMain(m *testing.M) {
        startCASSFixture()
        result := m.Run()
        os.Exit(result)
}

func startCASSFixture() {
        listener, err := net.Listen("tcp", ":10101")
        checkError(err)

        fmt.Println("listening")

        go func() {
                for {
                        conn, err := listener.Accept()
                        if err != nil {
                                log.Println(err)
                                continue
                        }

                        go handleConn(conn)
                }
        }()
}

func handleConn(c net.Conn) {
        defer c.Close()
        reader := bufio.NewReader(c)
        line, err := reader.ReadString('\n')
        checkError(err)

        log.Println("listener received:", line)

        if _, err = c.Write([]byte("Hello WA\n")); err != nil {
                log.Println(err)
                return
        }
}

func TestCASS(t *testing.T) {
        c := Cass{"localhost:10101"}

        reply, err := c.Send(Conversation{[]KVpair{{"ACTION", "NOTHING"}}})
        checkError(err)

        fmt.Println(reply)
}

func checkError(err error) {
        if err != nil {
                fmt.Fprintf(os.Stderr, "Fatal Error: %s", err.Error())
                os.Exit(1)
        }
}

output

listening
2015/06/19 09:14:45 listener received: ACTION=NOTHING

Hello WA

PASS
ok      test    0.011s