Here's an example:
#include <mpi.h>
double f() {
    double timer = MPI_Wtime();
    return timer;
}

What I am searching for is some set of mock MPI functions, so I can #include <mpi_mocks.h> instead of mpi.h and get it compiled without linking to MPI library. It could also be something like #define MOCK which will trigger this behavior in mpi.h. It feels, like I've stumbled on something like this, but I cannot find it right now.