WRITING-TESTS

Do what is EASIEST.  Having a test at all is more important than,
say, pretty failure output.

To add a test, open Main.hs, and add an entry to tests, e.g.:

    tests :: [TestEnv -> Test]
    tests =
        [ ...
        , TestLabel "Foo" . testFoo
        ]

    testFoo :: TestEnv -> Test
    testFoo TestEnv{..} = TestCase $ do
        meaningOfLife @?= 42
        2013 <- getCurrentYear
        return ()

Mnemonic for HUnit @=? and @?= operators:

 * `?` is the value whose correctness is in question

 * `=` is the expected value

If you move a test to a separate module, don't forget to add it to
"other-modules" in postgresql-simple.cabal .  Otherwise, the module will be
left out of the tarball generated by `cabal sdist`, and tests will fail to
build when installing from Hackage.

'TestEnv' (defined in Common.hs) contains information for accessing the
database.  `TestEnv{..}` is a record wildcard which brings the following
definitions into scope:

    conn     :: Connection
    withConn :: (Connection -> IO a) -> IO a

'conn' is a database connection shared by all the tests.
'withConn' can be used to open additional connections (to the same database).

'Test' is basically a tree of 'Assertion's, where 'Assertion' is just a type
alias for IO ().  See the [HUnit documentation][1] for more information.

 [1]: http://hackage.haskell.org/packages/archive/HUnit/latest/doc/html/Test-HUnit-Base.html