Using Boost.Test with MPI

I am currently developing an IPC library for the needs of my project. The library should establish a point-to point communication channel between two independent applications. It should be able to use different mechanisms for data transmission. I've written a set of unit tests using Boost.Test library to test different parts of the functionality. Currently, I am facing a slight inconvenience in a testing framework behaviour when it comes to running transport layer tests. Since, one of the transports is using MPI as a communication channel I need to run at least two processes (server and client), but I want to have only one instance of test (let's say server-side). Instead, when I run the test - I get two instances at once, which I wouldn't call a real problem but it is somewhat inconvenient. My code for testing is here:

void prepare_test() {
    MPI_Init(NULL, NULL);
    int size;
    int rank;
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    BOOST_TEST(size == 2);
    int color = rank;
    MPI_Comm_split(MPI_COMM_WORLD, color, rank, &small_comm);
    server = rank == 0;
    if (server) {
        mkdir(CLIENT_PATH.c_str(), 0777);
    }
}

void destroy_test() {
    if (server) {
        rmdir(CLIENT_PATH.c_str());
    }
    MPI_Finalize();
}

BOOST_DATA_TEST_CASE(connect_test,
                     bdata::make(generate_transports()),
                     each_transport) {
    prepare_test();
    Transport* current_transport = dynamic_cast<Transport*>(each_transport);
    int result;
    if (server) {
        current_transport->init_server(CLIENT_PATH, 1);
        result = current_transport->accept_connection(1);
        current_transport->destroy(CLIENT_PATH);
        BOOST_TEST(result == 0);
    } else {
        current_transport->init_client(CLIENT_PATH);
        result = current_transport->connect_address(0);
    }
    destroy_test();
}

One of the possible solutions that I can see is to create a separate binary with client code and run it along with the test binary (which should be launched with only one process now), but this solution feels a little clumsy, so maybe someone can suggest a better way of doing that?