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Nov. 23rd, 2012 11:12 pmQuite some time was spent today trying to create a test environment for a particularly convoluted SIP call flow (with the test harness code getting more and more twisted in an attempt to achieve it), until I had a wonderful moment when I realised that almost the entire call flow was completely irrelevant to the actual test.
The only part that mattered was a single message out of my system, and of that all I needed to know was where it was headed. And that depends on a single header in the incoming message, which only has to match reality if I need later requests/responses in the call to go to the right place. So my test suddenly became a lot easier: swap the high-level test harness out for another much more low-level one that lets you send whatever you want, craft a script to send a few INVITEs with completely bogus headers, and watch the results with a packet analyser. Success!
The only part that mattered was a single message out of my system, and of that all I needed to know was where it was headed. And that depends on a single header in the incoming message, which only has to match reality if I need later requests/responses in the call to go to the right place. So my test suddenly became a lot easier: swap the high-level test harness out for another much more low-level one that lets you send whatever you want, craft a script to send a few INVITEs with completely bogus headers, and watch the results with a packet analyser. Success!
