package main
import (
	"bufio"
	"fmt"
	"io"
	"os"
	"regexp"
	"strings"
)
func main() {
	response := askQuestion("What is your name?")
	fmt.Printf("Hello %s\n",response)
}
func askQuestion(question string) string {
	reader := bufio.NewReader(os.Stdin)
	answer := ""
	for {
		fmt.Printf("%s\n", question)
		input, err := reader.ReadString('\n')
		if err != nil {
			if err != io.EOF {
				panic(err)
			}
			break
		}
		if regexp.MustCompile(`[A-Z]{5}`).MatchString(strings.TrimSpace(input)) == true {
			answer = strings.TrimSpace(input)
			fmt.Printf("You entered %s\n", answer)
			break
		} else {
			fmt.Printf("3[31mYou must enter only 5 upper case letters.\n3[0m")
			continue
		}
	}
	return answer
}

package main
import (
	"bytes"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"reflect"
	"strings"
	"testing"
)
func TestAskQuestion(t *testing.T) {
	expected := "foo"
	entered := "foo"
	askQuestion("What is your last name?")
	oldStdout := os.Stdout
	r, w, _ := os.Pipe()
	os.Stdout = w
	fmt.Println(entered)
	outC := make(chan string)
	go func() {
		var buf bytes.Buffer
		io.Copy(&buf, r)
		outC <- buf.String()
	}()
	w.Close()
	os.Stdout = oldStdout
	out := strings.TrimSpace(<-outC)
	b, _ := ioutil.ReadAll(os.Stdin)
	t.Log(string(b))
	if !reflect.DeepEqual(expected, out) {
		t.Fatalf("Test Status Failure Issue. Got: '%v' expected %s", out, expected)
	}
}