@Test
public void testCopyFromWithAer() {

  final Aer filledValue = Aer.of("100", Unit.AERGO);
  final Aer nullValue = null;
  assertEquals(ByteString.copyFrom(positiveToByteArray(filledValue.getValue())),
      copyFrom(filledValue));
  assertEquals(ByteString.EMPTY, copyFrom(nullValue));
}