unit testingΒΆ

One of the major problem of doing science with simulations is that results found could be a mere result of a mistake in the software implementation. This problem is even stronger when emergent phenomena are expected. The first hedge against this problem is of course carefully checking the code. ABCE and Pythons brevity and readability are certainly helping this. However structured testing procedures create more robust software.

Currently all trade and exchange related as well as endowment, production utility and data logging facilities are unit tested. It is planned to extend unit testing to quotes, so that by version 0.6 all functions of the agents will be fully unit tested.

The modeler can run the unit testing facilities on his own system and therefore assert that on his own system the code runs correctly.

Unit testing is the testing of the testable part of a the software code. \cite{Xie2007}. As in ABCE the most crucial functions are the exchange of goods or information, the smallest testable unit is often a combination of two actions \cite{Aniche}. For example making an offer and then by a second agent accepting or rejecting it. The interaction and concurrent nature of ABCE simulation make it unpractical to use the standard unit testing procedures of Python.

\cite{Ellims2006} argue that unit-testing is economical. In the analysis of three projects they find that unit-testing finds errors in the code and argue that its cost is often exaggerated. We can therefore conclude that unit-testing is necessary and a cost efficient way of ensuring the correctness of the results of the simulation. For the modeler this is an additional incentive to use ABCE, if he implemented the simulation as a stand alone program he would either have to forgo the testing of the agent’s functions or write his own unit-testing facilities.