roman_tests.go

package main

import (
	"testing"

	"github.com/pkg/errors"
	"github.com/stretchr/testify/assert"
)

func TestAlwaysTrue(t *testing.T) {

	assert.True(t, true)
}

func Test0ReturnsError(t *testing.T) {
	_, err := convertToRomanNumeral(0)
	assert.Error(t, err)
}

func Test1ReturnsI(t *testing.T) {
	AssertRoman(t, "I", 1)
}

func Test2ReturnsII(t *testing.T) {

	AssertRoman(t, "II", 2)
}

func Test3ReturnsIII(t *testing.T) {

	AssertRoman(t, "III", 3)
}

func AssertRoman(t *testing.T, expected string, what int) {
	numeral, _ := convertToRomanNumeral(what)
	assert.Equal(t, expected, numeral)
}

func convertToRomanNumeral(n int) (string, error) {
	var translate = map[int]string{
		1: "I",
		2: "II",
		3: "III",
	}
	if 0 == n {
		return "", errors.New("0 invalid")
	}
	return translate[n], nil
}