pytest-xdist 1.8

py.test xdist plugin for distributed testing and loop-on-failing modes

Speed up test runs by sending tests to multiple CPUs

To send tests to multiple CPUs, type:

py.test -n NUM

Especially for longer running tests or tests requiring a lot of IO this can lead to considerable speed ups.

Running tests in a Python subprocess

To instantiate a python2.4 sub process and send tests to it, you may type:

py.test -d --tx popen//python=python2.4

This will start a subprocess which is run with the "python2.4" Python interpreter, found in your system binary lookup path.

If you prefix the --tx option value like this:

--tx 3*popen//python=python2.4

then three subprocesses would be created and tests will be load-balanced across these three processes.

Sending tests to remote SSH accounts

Suppose you have a package mypkg which contains some tests that you can successfully run locally. And you have a ssh-reachable machine myhost. Then you can ad-hoc distribute your tests by typing:

py.test -d --tx ssh=myhostpopen --rsyncdir mypkg mypkg

This will synchronize your mypkg package directory to an remote ssh account and then locally collect tests and send them to remote places for execution.

You can specify multiple --rsyncdir directories to be sent to the remote side.

NOTE: For py.test to collect and send tests correctly you not only need to make sure all code and tests directories are rsynced, but that any test (sub) directory also has an __init__.py file because internally py.test references tests as a fully qualified python module path. You will otherwise get strange errors during setup of the remote side.

Sending tests to remote Socket Servers

Download the single-module socketserver.py Python program and run it like this:

python socketserver.py

It will tell you that it starts listening on the default port. You can now on your home machine specify this new socket host with something like this:

py.test -d --tx socket=192.168.1.102:8888 --rsyncdir mypkg mypkg

Running tests on many platforms at once

The basic command to run tests on multiple platforms is:

py.test --dist=each --tx=spec1 --tx=spec2

If you specify a windows host, an OSX host and a Linux environment this command will send each tests to all platforms - and report back failures from all platforms at once. The specifications strings use the xspec syntax.

Specifying test exec environments in an ini file

pytest (since version 2.0) supports ini-style cofiguration. You can for example make running with three subprocesses your default like this:

[pytest]
addopts = -n3

You can also add default environments like this:

[pytest]
addopts = --tx ssh=myhost//python=python2.5 --tx ssh=myhost//python=python2.6

and then just type:

py.test --dist=each

to run tests in each of the environments.

Specifying "rsync" dirs in an ini-file

In a tox.ini or setup.cfg file in your root project directory you may specify directories to include or to exclude in synchronisation:

[pytest]
rsyncdirs = . mypkg helperpkg
rsyncignore = .hg

These directory specifications are relative to the directory where the configuration file was found.