The `pytest-xdist`_ plugin extends py.test with some unique
test execution modes:

* test run parallelization_: if you have multiple CPUs or hosts you can use
those for a combined test run. This allows to speed up
development or to use special resources of `remote machines`_.

* ``--boxed``: (not available on Windows) run each test in a boxed_
subprocess to survive ``SEGFAULTS`` or otherwise dying processes

* ``--looponfail``: run your tests repeatedly in a subprocess. After each run
py.test waits until a file in your project changes and then re-runs
the previously failing tests. This is repeated until all tests pass
after which again a full run is performed.

* `Multi-Platform`_ coverage: you can specify different Python interpreters
or different platforms and run tests in parallel on all of them.

Before running tests remotely, ``py.test`` efficiently "rsyncs" your
program source code to the remote place. All test results
are reported back and displayed to your local terminal.
You may specify different Python versions and interpreters.