How to sleep a million years (2013)
An example usage from the article:    $ time sleep 12
    real    0m12.003s

    $ time ./fluxcapacitor -- sleep 12
    real    0m0.057s

In the author's words:    Fluxcapacitor is really good at speeding
    up client/server or protocol tests.

    Actually fluxcapacitor was originally
    created to speed up the sockjs-protocol
    test suite. It wasn't possible to mock
    up a time library - we needed to run
    the tests against any sockjs http server,
    whether it's in erlang, node.js or
    python. It turns out the only way to run
    timeout-related tests in a reasonable
    time is to use fluxcapacitor.

    You might ask how fluxcapacitor works.
    In short - it uses ptrace to catch
    syscalls like clock_gettime or
    gettimeofday and overwrite the kernel
    response with a fake time.
    Additionally it short-circuits
    syscalls that can block for a timeout
    like select or poll. For technical
    details see the README.

It seems that this library might be useful to anyone needing to test communication protocols by helping tickle those edge cases that happen with timing.