First commit

go.mod

@@ -0,0 +1 @@
+module github.com/mimiyanwk/stringutil

reverse.go

@@ -0,0 +1,9 @@
+package stringutil
+
+func Reverse(s string) string {
+	r := []rune(s)
+	for i, j := 0, len(r)-1; i < len(r)/2; i, j = i+1, j-1 {
+		r[i], r[j] = r[j], r[i]
+	}
+	return string(r)
+}

reverse_test.go

@@ -0,0 +1,21 @@
+package stringutil
+
+import (
+	"testing"
+)
+
+func TestReverse(t *testing.T) {
+	cases := []struct {
+		in, want string
+	}{
+		{"Hello, world", "dlrow ,olleH"},
+		{"Hello, 世界", "界世 ,olleH"},
+		{"", ""},
+	}
+	for _, c := range cases {
+		got := Reverse(c.in)
+		if got != c.want {
+			t.Errorf("Reverse(%q) == %q, want %q", c.in, got, c.want)
+		}
+	}
+}