Overview

Description

The Python backend provides - in tandem with ECSpooler - automatic

testing of Python programs. Therefore the backend compares the

output of a program with the output of a model solution for a set of

test data.

Prerequisites

* A UNIX or UNIX-like operating system, e.g., NetBSD, Solaris, Mac

OS X, or Linux.

Prolog backend does run on Windows (with some restrictions), but

this is neither supported nor recommended.

* "Python":http://python.org/

* "ECSpooler":http://wdok.cs.uni-magdeburg.de/software/ecspooler

* ECSpooler is primarily intended to be used via the

"ECAutoAssessmentBox":http://plone.org/products/ecautoassessmentbox

Plone product. So you will normally have a Plone installation

with ECAutoAssessmentBox.

Installation

* Unzip this archive under the 'backends' directory of your

ECSpooler installation (for example '/opt/ESpooler/backends/').

* Adjust value for INTERPRETER in the script

'backends/python/python.sh' to your system environemnt.

* Make sure that the script 'backends/python/python.sh' is

executable.

Security

When executing unknown code, you have to take security precautions,

e.g., by using chroot, jails, or systrace. These mechanisms are,

however, system-dependent, so we cannot give detailed installation

instructions.

If you are using "systrace":http://www.systrace.org/, adjust the

shell scripts 'backends/python/python+systrace' to your system

environment and set *INTERPRETER* in

'backends/python/config.py' to this script.

Please be aware of the risks if you are *not* able to deal with the

configuration issues.

Quick Start

After installation first start ECSpooler (see the ECSpooler

documentation for details). Then you should be able to start the

Java backend using the following command (you may have to specify

the path)::

backendctl -u root -p bazquux Python start

If you run this command as root, the process will be started as user

"nobody".

Once the backend is running, check the status of the backend using::

spoolerctl -u root -p bazquux status

and get a response similar to::

{'queue': 0, 'backends': ['python'], 'pid': 26437, 'results': 0}

For administrative tasks such as starting/stopping backends

authentication is required. Therefore ECSpooler ships with a

password file ('etc/passwd') containing a user root with default

password "bazquux".

Testing a Python program with the Python backend requires a model

solution and a set of test data, e.g.,

* Model solution::

def square(x): return x * x

* Test data (one test call per line)::

square(0)

square(2)

square(3)

The Python backend supports TODO compare modes:

* simple - the results of the student and model solutions for same

test data must be equal

* permutation - accept student solution if the returned list is a

permutation of the result from the model solution

Support

For questions and discussions about backends, please join the

"eduComponents mailing

list":https://listserv.uni-magdeburg.de/mailman/listinfo/educomponents.

Credits

The Python backend was written by "Mario

Amelung":mailto:mario.amelung@gmx.de.

License

The Python backend is licensed under the

"GPL":http://opensource.org/licenses/gpl-license.

Copyright © 2007-2011 Otto-von-Guericke-Universität Magdeburg

The Python backend is free software; you can redistribute it and/or

modify it under the terms of the GNU General Public License as

published by the Free Software Foundation; either version 2 of the

License, or (at your option) any later version.

The Python backend is distributed in the hope that it will be

useful, but WITHOUT ANY WARRANTY; without even the implied warranty

of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

General Public License for more details.

You should have received a copy of the GNU General Public License

along with ECSpooler; if not, write to the Free Software Foundation,

Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA