Friday, 11 January 2008

Network system testing

Testing is always helpful in development, large projects often undergo testing at different levels: unit testing, integration testing, and performance testing. With a multicast network protocol none of these cover actual testing of the protocol between hosts, so we create a new method: network system testing. We want to test the OpenPGM stack and the API it provides to the application developer as pictured below on the top right.

Some tests need an external source to drive functionality in the stack, the Simulator is used for this task. In order to verify the packets sent out by the stack are correct with have the Monitor.

In order to build an extensive set of tests that can be reliably re-run we want to use automated testing. This means some form of scripting of all three systems and synchronisation between how each is run. The Tester host runs a script that remotely controls and receives feedback from each of the three test systems. All communication is via stdin and stdout, including the monitor with is a glorified version of tcpdump but shows PGM packets in JSON form.

To make everything platform agnostic and to ease development all scripts are in Perl, modules can be used to SSH into remote hosts, perform high resolution timing, process JSON representation of PGM packets, etc.