I discovered Jason Pellerin's nose test discovery and execution tool when I started using TurboGears. My first forays into test driven development and automated Python testing weren't all that successful though. Then this talk by Jonathan Hartley, and this one by Titus Brown at PyCon 2008, and a lobby chat with Jonathan just before I left Chicago got me thinking differently, and more seriously about automated testing. A few days later, the penny dropped, and I'm a convert!
Then I came across Jeff Winkler's nosy script that runs <code> nose</code> whenever a source file has changed. I'd thought about doing something like that but was thinking I'd have to use some kind of continuous integration system like buildbot, and that seemed like a whole lot of trouble for some little personal projects. Jeff's trick for calculating a checksum for the source files makes it all very, very easy. His original nosy.py script is less than 20 lines long!
I liked nosy on sight but after playing with it for a short time wanted to add features and flexibility. I like to keep my test code in a tests/ directory, separate from my project code. I wanted nose to run whenever I changed either the project code, or the test code. I wanted to be able to change the way nose ran, turning options like -s and -v on or off, and specifying particular parts of the test suite to run via command line arguments.
So, I decided that nosy needed the option of having a configuration file. Of course that meant that it needed a command line processor. ConfigParser and optparse from the Python standard library to the rescue, and we have my version of nosy:
$ nosy -h
Usage: nosy [options]
Automatically run nose whenever source files change.
Options:
-h, --help show this help message and exit
-c CONFIG_FILE, --config=CONFIG_FILE
Configuration file path and name
You should be able to install nosy with:
$ easy_install -f http://douglatornell.ca/software/python nosy
Throw a config file something like this sample:
# Sample config file for nosy # Including this file in the paths to check allows you to change # nose's behaviour on the fly. [nosy] # Paths to check for changed files; changes cause nose to be run paths = *.py tests/*.py tests/nosy.cfg # Command line options to pass to nose options = -s # Command line arguments to pass to nose; e.g. part of test suite to run tests = tests/unit_tests.py # end of file
in your tests/ directory as nosy.cfg, launch nosy with:
$ nosy -c tests/nosy.cfg
and away you go. nose will run whenever *.py in the current directory, or tests/*.py, or tests/nosy.cfg change.
The paths option in the config file controls which files are monitored for changes. Putting the config file itself in that list allows you to change how nose runs without having to stop and restart nosy.
options are the command line options to pass to nose. Use -v to turn on verbose output, or -a foo to run only the tests with attribute foo.
tests are the command line arguments to pass to nose, used to select specific tests to run.