-- <PRE>
module HUnitDemo where

import Test.HUnit(Test(TestCase,TestList),assertEqual,runTestTT)
import Test.QuickCheck



-- 1) write a type for the function. Make its body undefined
len:: [ a ] -> Int
len [] = 0
len (x:xs) = 1 + len xs


-- 2) make some examples, and express them as HUnit assertions
-- len [] --> 0
-- len [1,1,1,1] --> 4
-- len [1,2] --> 2

ex1 = assertEqual "empty" (len [])  0
ex2 = assertEqual "all the same" (len [1,1,1,1]) 4
ex3 = assertEqual "two" (len [1,2]) 2

-- 3) Collect all the tests together
-- By convention we use the name tests
-- to collect all the Unit-tests in one file together.


lenTest = TestList[TestCase ex1, TestCase ex2, TestCase ex3]
tests = runTestTT (TestList[lenTest,sumTests])

-- 4) Then fill in the definition until all tests are passed!

---------------------------------------------------------
-- Now try it for the sum function

-- 1) write a type for the function. Make its body undefined

summ:: [Int] -> Int
summ [] = 0
summ (x:xs) = x + summ xs

-- 2) make some examples, and express them as HUnit assertions

ex4 = assertEqual "sum 0" (summ []) 0
ex5 = assertEqual "sum 2" (summ [2]) 2
ex6= assertEqual "sum 10" (summ [5,4,1]) 10

sumTests = TestList [TestCase ex4, TestCase ex5, TestCase ex6]

-- 3) Collect all the tests together

-- 4) Then fill in the definition until all tests are passed!


-- </PRE>