Go from introduction to practice - polymorphism (note)

package main

import (
	"fmt"
	"testing"
)

type Code string

type Programmer interface {
    
	WriteHelloWorld() Code
}

type GoProgrammer struct {
    
}

func (p *GoProgrammer) WriteHelloWorld() Code {
    
	return "fmt.Println(\"Hello world\")"
}

type JavaProgrammer struct {
    
}

func (p *JavaProgrammer) WriteHelloWorld() Code {
    
	return "System.out.Println(\"Hello world\")"
}

func writeFirstProgram(p Programmer) {
    
	fmt.Printf("%T %v\n", p, p.WriteHelloWorld())
}

func TestPolymorphism(t *testing.T) {
    
	goProg := new(GoProgrammer)
	javaProg := new(JavaProgrammer)
	writeFirstProgram(goProg)
	writeFirstProgram(javaProg)
}