How to test code that loops forever

I have an app (epazote) that once starts runs forever but I want to test some values before it blocks/waits until ctrl+c is pressed or is killed.

Here is an small example: http://ift.tt/1TkvEVd

package main

import (
    "fmt"
    "os"
    "os/signal"
)

type IAddString interface {
    AddString(string)
}

type addString struct{}

func (self *addString) AddString(s string) {
    fmt.Println(s)
}

func block(a IAddString, s string) {

    // test this
    a.AddString(s)


    // ignore this while testing
    block := make(chan os.Signal)
    signal.Notify(block, os.Interrupt, os.Kill)

    for {
        signalType := <-block
        switch signalType {

        default:
            signal.Stop(block)
            fmt.Printf("%q signal received.", signalType)
            os.Exit(0)
        }
    }
}

func main() {
    a := &addString{}
    block(a, "foo")
}

I would like to know if is posible to ignore some parts of the code while testing, or how to test this cases, I have implemented an interface, in this case for testing AddString that helped me to test some parts but have no idea of how to avoid the "block" and test.

Any ideas?