sum := fmt.Sprintf("%x", h.Sum())
	want := "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9"
	if sum != want {
		t.Errorf("hash(hello world) = %v, want %v", sum, want)
	}
}

func TestHashFile(t *testing.T) {
	f, err := os.CreateTemp("", "cmd-go-test-")
	if err != nil {
		t.Fatal(err)
	}
	name := f.Name()
	fmt.Fprintf(f, "hello world")
	defer os.Remove(name)
	if err := f.Close(); err != nil {