Abstract: A computer executable test language is provided for testing a component of a distributed transaction processing system implemented in accordance with the X/Open Distributed Transaction Processing model and supporting the XATMI application programming interface of said model (XATMI API). The test language comprises a plurality of commands, each command corresponding to a respective one of the function calls of the XATMI API. At least some of the commands of the test language have a syntax and semantics that requires a lesser number of parameters to be supplied with the command than the formal syntax of the corresponding function call of the XATMI API, thus hiding the complexities of the XATMI API from the test operator.