feat: introduce random package (#58)

random package generate random string

random/random.go

@@ -0,0 +1,32 @@
+package random
+
+import (
+	"crypto/rand"
+	"io"
+)
+
+func GenerateAlphabets(length int) string {
+	const letters = "ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
+	return generateRandomString(letters, length)
+}
+
+func GenerateAlphabetsLowerCase(length int) string {
+	const letters = "abcdefghijkmnopqrstuvwxyz"
+	return generateRandomString(letters, length)
+}
+
+func GenerateBase58(length int) string {
+	const letters = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
+	return generateRandomString(letters, length)
+}
+
+func generateRandomString(letters string, length int) string {
+	b := make([]byte, length)
+	_, _ = io.ReadFull(rand.Reader, b)
+
+	var result string
+	for _, v := range b {
+		result += string(letters[int(v)%len(letters)])
+	}
+	return result
+}

random/random_test.go

@@ -0,0 +1,24 @@
+package random_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/tier4/x-go/random"
+)
+
+func TestGenerateAlphabets(t *testing.T) {
+	t.Parallel()
+	assert.Regexp(t, "^[a-zA-Z]{50}$", random.GenerateAlphabets(50))
+}
+
+func TestGenerateAlphabetsLowerCase(t *testing.T) {
+	t.Parallel()
+	assert.Regexp(t, "^[a-z]{50}$", random.GenerateAlphabetsLowerCase(50))
+}
+
+func TestGenerateBase58(t *testing.T) {
+	t.Parallel()
+	assert.Regexp(t, "^[123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz]{50}$", random.GenerateBase58(50))
+}