content: == RUNNING ==
  
  Compile the test suite:
  
    ghc -package test-framework -package test-framework-quickcheck2 \
            -package test-framework-hunit -threaded Example.lhs -o Example
  
  To run the test suite with the default options, simply execute the
  resulting binary:
  
    ./Example
  
  Test options can also be supplied on the command-line:
  
    ./Example --maximum-generated-tests=5000 +RTS -N2
  
  To see the available options, run:
  
    ./Example --help
  
  These options can also be specified in the code. An alternate main
  function, mainWithOpts, with compile-time options is provided:
  
    ghc -package test-framework -package test-framework-quickcheck2 \
            -package test-framework-hunit -main-is mainWithOpts     \
            -threaded Example.lhs -o Example
    ./Example
  
  == ATTRIBUTION ==
  
  The example properties come from the parallel QuickCheck driver (pqc),
  see http://code.haskell.org/~dons/code/pqc/.  The BSD license is repeated
  below, per the licensing conditions of pqc.
  
  == LICENSING ==
  
  Copyright Don Stewart 2006.
  
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:
  
      * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
  
      * Redistributions in binary form must reproduce the above
        copyright notice, this list of conditions and the following
        disclaimer in the documentation and/or other materials provided
        with the distribution.
  
      * Neither the name of Don Stewart nor the names of other
        contributors may be used to endorse or promote products derived
        from this software without specific prior written permission.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  \begin{code}
  
  module Main
  where
  
  import Data.Monoid (mempty)
  import Test.Framework (defaultMain, defaultMainWithOpts, testGroup)
  import Test.Framework.Options (TestOptions, TestOptions'(..))
  import Test.Framework.Runners.Options (RunnerOptions, RunnerOptions'(..))
  import Test.Framework.Providers.HUnit
  import Test.Framework.Providers.QuickCheck2 (testProperty)
  
  import Test.QuickCheck
  import Test.HUnit
  
  import Data.List
  
  main = defaultMain tests
  
  mainWithOpts = do
    -- Test options can also be specified in the code. The TestOptions
    -- type is an instance of the Monoid type class, so the easiest way
    -- to get an empty set of options is with `mempty`.
    let empty_test_opts = mempty :: TestOptions
  
    -- We update the empty TestOptions with our desired values.
    let my_test_opts = empty_test_opts {
      topt_maximum_generated_tests = Just 500
    }
  
    -- Now we create an empty RunnerOptions in the same way, and add
    -- our TestOptions to it.
    let empty_runner_opts = mempty :: RunnerOptions
    let my_runner_opts = empty_runner_opts {
      ropt_test_options = Just my_test_opts
    }
  
    defaultMainWithOpts tests my_runner_opts
  
  tests = [
          testGroup "Sorting Group 1" [
                  testProperty "sort1" prop_sort1,
                  testProperty "sort2" prop_sort2,
                  testProperty "sort3" prop_sort3
              ],
          testGroup "Sorting Group 2" [
                  testGroup "Nested Group 1" [
                         testProperty "sort4" prop_sort4,
                         testProperty "sort5" prop_sort5,
                         testProperty "sort6" prop_sort6
                       ],
                  testProperty "sort7" prop_sort7,
                  testCase "sort8" test_sort8,
                  testCase "sort9" test_sort9
              ]
      ]
  
  
  prop_sort1 xs = sort xs == sortBy compare xs
    where types = (xs :: [Int])
  
  prop_sort2 xs =
          (not (null xs)) ==>
          (head (sort xs) == minimum xs)
    where types = (xs :: [Int])
  
  prop_sort3 xs = (not (null xs)) ==>
          last (sort xs) == maximum xs
    where types = (xs :: [Int])
  
  prop_sort4 xs ys =
          (not (null xs)) ==>
          (not (null ys)) ==>
          (head (sort (xs ++ ys)) == min (minimum xs) (minimum ys))
    where types = (xs :: [Int], ys :: [Int])
  
  prop_sort5 xs ys =
          (not (null xs)) ==>
          (not (null ys)) ==>
          (head (sort (xs ++ ys)) == max (maximum xs) (maximum ys))
    where types = (xs :: [Int], ys :: [Int])
  
  prop_sort6 xs ys =
          (not (null xs)) ==>
          (not (null ys)) ==>
          (last (sort (xs ++ ys)) == max (maximum xs) (maximum ys))
    where types = (xs :: [Int], ys :: [Int])
  
  prop_sort7 xs = if null xs then error "This property deliberately contains a user error" else True
    where types = (xs :: [Int])
  
  test_sort8 = sort [8, 7, 2, 5, 4, 9, 6, 1, 0, 3] @?= [0..9]
  
  test_sort9 = error "This test deliberately contains a user error"
  \end{code}
  