TestAllTypesMicro msg = new TestAllTypesMicro();
assertFalse(msg.hasOptionalSint32());
msg.setOptionalSint32(123);
assertTrue(msg.hasOptionalSint32());
assertEquals(123, msg.getOptionalSint32());
msg.clearOptionalSint32();
assertFalse(msg.hasOptionalSint32());
msg.clearOptionalSint32()
.setOptionalSint32(456);
assertTrue(msg.hasOptionalSint32());
msg.clear();