On 01/05/2011 03:44 AM, Jonathan Geddes wrote:
When I write Haskell code, I write functions (and monadic actions) that are either a) so trivial that writing any kind of unit/property test seems silly, or are b) composed of other trivial functions using equally-trivial combinators.
"There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies. And the other way is to make it so complicated that there are no obvious deficiencies." -- C.A.R. Hoare
If you actually manage to do the former, I'd say you don't need to test those parts in isolation.
That said, I disagree with you overall. The Haskell type system is simply not rich enough to guarantee everything you might need. Even if it was, it would take a lot of work to encode all your invariants, probably more work than writing tests would have been (although there are obvious advantages to the former as far as having a high level of assurance that your code is correct).
Haskell has some awesome testing tool, and I highly recommend getting acquainted with them. In particular, you should definitely learn how to use QuickCheck, which allows you to easily check high-level properties about your code; this is beyond what most traditional unit tests could hope to achieve. I tend to use QuickCheck, SmallCheck, *and* LazySmallCheck in my test suites, as I feel that they complement each other well. HUnit is probably the main one for traditional unit tests. I admit I have never used it, and I'm not sure whether I'm missing out on anything. There are also some pretty nice test frameworks out there to help you manage all your tests, although they could probably use a little more work overall.
- Jake _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
