The MPI Testing Tool (MTT) is a project initiated by the Open MPI project for comprehensive, distributed testing of MPI software packages. MTT is designed to be run in a fully automated fashion (e.g., able to be run via cron on a regular basis). It focuses on providing correctness and performance testing across many different impementations and versions of MPI software. The Open MPI Project uses MTT mainly for nightly regression testing of its own software, but also uses it for performance comparisons to other MPI implementations. Note that MTT is not dependent on/does not require Open MPI.