I think this needs expanding + should be quite definite
 * tests for any new functionality
   * every function
   * major operational cases
 * tests exercising code where bugs were fixed (i.e. things that *fail with the old code*, but work with the new)

There's quite a bit to know about how we organise tests + what we expect.
I'm hoping we're now "close" to being more definite about the testing structures ?
Refer - https://groups.google.com/forum/#!topic/scitools-iris-dev/OMbwsyyLszI