In various embodiments, a data signal is received from a computer system. The data signal includes an order for an instrument and further includes an indicator. The indicator indicates that the order is one of a real order or a test order. The order is a test order. A test order that specifies a bid cannot bind an originator of the test order to tender money. A test order that specifies an offer cannot bind the originator of the test order to tender the instrument. The order is matched to another order. Whether the order is a test order or a real order is determined, based at least in part on the indicator.