ronjeffries / REMOVEacm.org (Ron Jeffries) wrote (abridged):
> What you didn't much address is whether this little example needs more
> tests or not.  In my view, it does not (after the one for not a
> triangle, which has been provided). It certainly seems not to require
> 22.

That the function's result should not depend on the order of its arguments 
is, in my view, an important fact that should be made more explicit than 
it currently is. We can deduce it from the function's implementation, or 
from the function's name plus what we know about triangles, but I'm not 
sure that is enough to satisfy the "Once" part of "Once and Only Once".

I suspect we need some more support from the test rig; some mechanism 
which will generate all permutations of a collection of arguments and 
#perform them. There are 6 permutations, and we need to test at least the 
3 normal cases, but I would tend to regard the whole thing as 1 test 
rather than 18.

  Dave Harris, Nottingham, UK | "Weave a circle round him thrice,
      brangdon / cix.co.uk      |   And close your eyes with holy dread,
                              |  For he on honey dew hath fed
 http://www.bhresearch.co.uk/ |   And drunk the milk of Paradise."