It could be anything. It could be a company standard written by someone like the Cobra Oil & Gas Refinery, an acronym for something like a "Coolant Boiling in Rod Arrays" Simulations Test, or even a language barrier. For example in Spanish a "cobra" test would mean something to the effect of a test that you have to pay for (and I know that Spanish speakers on this forum can correct me if I am wrong). In that case they might just mean for you to pay for any optional testing that is offered with a price adder.
This is not a test I have ever heard of and if you can't easily find it on the internet it is probably not available from anyone but your source. I would go back to them and ask for clarifications on what they meant and request information on the test.