units-2.2: Tests/README.md

`units` Test Design
===================

There are two kinds of test:

 - `Compile` tests test only compilation, not any functionality. A new `Compile`
   test should be placed in the `Compile` directory and imported from
   `Tests.Main`, in alphabetical order with the others.

 - Other tests test both compilation and some functionality. These use the
   [`tasty`](http://hackage.haskell.org/package/tasty) testing framework,
   avaiable on Hackage. Each of these tests should export a 
   `tests :: TestTree` definition which contain all the tests in
   the module. Then, this `tests` should be imported and run from within
   `Tests.Main`, following the style there.

To run the tests, just say `cabal test`. You will need to say `git submodule
update --init` to download the contents of `units-defs`, necessary for testing
purposes.