errs := fmt.Sprintf("binary.%s: some values are not fixed-sized in type *binary.Person", enc.name)
			if err.Error() != errs {
				t.Fatalf("got %q, want %q", err, errs)
			}
		})
	}
}

func TestAppendAllocs(t *testing.T) {
	buf := make([]byte, 0, Size(&s))
	var err error
	allocs := testing.AllocsPerRun(1, func() {
		_, err = Append(buf, LittleEndian, &s)
	})
	if err != nil {
		t.Fatal("Append failed:", err)