pragprog.com/rggo/firstProgram/wc/main_test.go

package main

import (
	"bytes"
	"testing"
)

func TestCountWords(t *testing.T) {
	b := bytes.NewBufferString("hello world world2 world3 world4\n")

	exp := 5
	res := count(b)
	if res != exp {
		t.Errorf("Expected %d, got %d instead.\n", exp, res)
	}
}