diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,8 @@
+2017-06-15 Ivan Perez <ivan.perez@keera.co.uk>
+
+        * keera-posture.cabal: Bump (0.2.4.3).
+        * Adds SDL_mixer as dependency on every OS (needed by Launchpad PPA).
+
 2017-05-08 Ivan Perez <ivan.perez@keera.co.uk>
 
         * keera-posture.cabal: Bump (0.2.4.1).
diff --git a/keera-posture.cabal b/keera-posture.cabal
--- a/keera-posture.cabal
+++ b/keera-posture.cabal
@@ -1,75 +1,41 @@
--- auto-generated by cabal init. For additional options, see
--- http://www.haskell.org/cabal/release/cabal-latest/doc/users-guide/authors.html#pkg-descr.
--- The name of the package.
 Name:                keera-posture
-
--- The package version. See the Haskell package versioning policy
--- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for
--- standards guiding when and how versions should be incremented.
-Version:             0.2.4.1
-
--- A short (one-line) description of the package.
+Version:             0.2.4.3
 Synopsis:            Get notifications when your sitting posture is inappropriate.
-
--- A longer description of the package.
 Description:         A program that notifies when you sit in a straining position.
-
--- URL for the project homepage or repository.
 Homepage:            http://keera.co.uk/projects/keera-posture
-
--- The license under which the package is released.
 License:             OtherLicense
-
--- The file containing the license text.
 License-file:        LICENSE
-
--- The package author(s).
 Author:              Ivan Perez
-
--- An email address to which users can send suggestions, bug reports,
--- and patches.
 Maintainer:          support@keera.co.uk
 
--- A copyright notice.
--- Copyright:
-
--- Stability of the package (experimental, provisional, stable...)
--- Stability:           Experimental
-
-Tested-With:         GHC == 7.6.3
-
+Copyright:           2010-2017 Keera Studios
+Tested-With:         GHC == 7.8.4
 Category:            AI
-
 Build-type:          Simple
 
 Data-files: data/Interface.glade data/warning.wav data/*.png data/haarcascade_frontalface_alt.xml
 
--- Extra files to be distributed with the package, such as examples or
--- a README.
 Extra-source-files:  README
                      CHANGELOG
 
--- Constraint on the version of Cabal needed to build this package.
-Cabal-version:       >=1.6
+cabal-version:       >= 1.10
 
 Executable keera-posture
-  -- .hs or .lhs file containing the Main module.
+  default-language: Haskell2010
+
   Main-is: Main.hs
   hs-source-dirs: src/
 
   if os(windows)
-   ghc-options: -threaded -Wall -fno-warn-unused-do-bind -O2
-   -- ghc-options: -threaded -Wall -fno-warn-unused-do-bind -O2 -optl-mwindows
-   -- ghc-options: -threaded -Wall -fno-warn-unused-do-bind -O2 -rtsopts=all
+   ghc-options: -threaded -Wall -fno-warn-unused-do-bind -O2 -optl-mwindows
   else
    ghc-options: -threaded -Wall -fno-warn-unused-do-bind
    -- ghc-options: -threaded -Wall -fno-warn-unused-do-bind -O2 obj/OpenCVGtkPixbuf.o
 
-  if os(windows)
-   extra-libraries: SDL_mixer
+  -- if os(windows)
+  -- TODO: This should be in SDL-mixer, shouldn't it?
+  extra-libraries: SDL_mixer
 
-  -- Packages needed in order to build this package.
-  -- Build-depends:
   if os(windows)
     Build-depends: base >= 4.0 && < 5,
                    containers,
@@ -214,3 +180,41 @@
 source-repository head
   type:     git
   location: https://github.com/keera-studios/keera-posture.git
+
+-- You can disable the hlint test suite with -f-test-hlint
+flag test-hlint
+  default: False
+  manual: True
+
+-- You can disable the haddock coverage test suite with -f-test-doc-coverage
+flag test-doc-coverage
+  default: False
+  manual: True
+
+test-suite hlint
+  type: exitcode-stdio-1.0
+  main-is: hlint.hs
+  hs-source-dirs: tests
+  if !flag(test-hlint)
+    buildable: False
+  else
+    build-depends:
+      base,
+      hlint >= 1.7
+
+-- Verify that the code is thoroughly documented
+test-suite haddock-coverage
+  type: exitcode-stdio-1.0
+  main-is: HaddockCoverage.hs
+  ghc-options: -Wall
+  hs-source-dirs: tests
+
+  if !flag(test-doc-coverage)
+    buildable: False
+  else
+    build-depends:
+      base >= 4 && < 5,
+      directory,
+      filepath,
+      process,
+      regex-posix
diff --git a/tests/HaddockCoverage.hs b/tests/HaddockCoverage.hs
new file mode 100644
--- /dev/null
+++ b/tests/HaddockCoverage.hs
@@ -0,0 +1,91 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Main (HaddockCoverage)
+-- Copyright   :  (C) 2015 Ivan Perez
+-- License     :  BSD-style (see the file LICENSE)
+-- Maintainer  :  Ivan Perez <ivan.perez@keera.co.uk>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+-- Copyright notice: This file borrows code
+-- https://hackage.haskell.org/package/lens-4.7/src/tests/doctests.hsc
+-- which is itself licensed BSD-style as well.
+--
+-- Run haddock on a source tree and report if anything in any
+-- module is not documented.
+-----------------------------------------------------------------------------
+module Main where
+
+import Control.Applicative
+import Control.Monad
+import Data.List
+import System.Directory
+import System.Exit
+import System.FilePath
+import System.IO
+import System.Process
+import Text.Regex.Posix
+
+main :: IO ()
+main = do
+  -- Find haskell modules
+  -- TODO: Ideally cabal should do this (provide us with the
+  -- list of modules). An alternative would be to use cabal haddock
+  -- but that would need a --no-html argument or something like that.
+  -- Alternatively, we could use cabal haddock with additional arguments.
+  --
+  -- See:
+  -- https://github.com/keera-studios/haddock/commit/d5d752943c4e5c6c9ffcdde4dc136fcee967c495
+  -- https://github.com/haskell/haddock/issues/309#issuecomment-150811929
+  files <- getSources
+
+  let haddockArgs = [ "--no-warnings", "--ignore-all-exports" ] ++ files
+  let cabalArgs   = [ "exec", "--", "haddock" ] ++ haddockArgs
+  (code, out, _err) <- readProcessWithExitCode "cabal" cabalArgs ""
+
+  -- Filter out coverage lines, and find those that denote undocumented
+  -- modules.
+  --
+  -- TODO: is there a way to annotate a function as self-documenting,
+  -- in the same way we do with ANN for hlint?
+  let isIncompleteModule :: String -> Bool
+      isIncompleteModule line = isCoverageLine line && not (line =~ "^ *100%")
+        where isCoverageLine :: String -> Bool
+              isCoverageLine line = line =~ "^ *[0-9]+%"
+
+  let incompleteModules :: [String]
+      incompleteModules = filter isIncompleteModule $ lines out
+
+  -- Based on the result of haddock, report errors and exit.
+  -- Note that, unline haddock, this script does not
+  -- output anything to stdout. It uses stderr instead
+  -- (as it should).
+  case (code, incompleteModules) of
+    (ExitSuccess  , []) -> return ()
+    -- (ExitFailure _, _)  -> exitFailure
+    (_            , _)  -> do
+      hPutStrLn stderr "The following modules are not fully documented:"
+      mapM_ (hPutStrLn stderr) incompleteModules
+      exitFailure
+
+getSources :: IO [FilePath]
+getSources = filter isHaskellFile <$> go "src"
+  where
+    go dir = do
+      (dirs, files) <- getFilesAndDirectories dir
+      (files ++) . concat <$> mapM go dirs
+
+    isHaskellFile fp = (isSuffixOf ".hs" fp || isSuffixOf ".lhs" fp)
+                     && not (any (`isSuffixOf` fp) excludedFiles)
+
+    excludedFiles = [ ]
+
+getFilesAndDirectories :: FilePath -> IO ([FilePath], [FilePath])
+getFilesAndDirectories dir = do
+  c <- map (dir </>) . filter (`notElem` ["..", "."]) <$> getDirectoryContents dir
+  (,) <$> filterM doesDirectoryExist c <*> filterM doesFileExist c
+
+-- find-based implementation (not portable)
+--
+-- getSources :: IO [FilePath]
+-- getSources = fmap lines $ readProcess "find" ["src/", "-iname", "*hs"] ""
diff --git a/tests/hlint.hs b/tests/hlint.hs
new file mode 100644
--- /dev/null
+++ b/tests/hlint.hs
@@ -0,0 +1,23 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Main (hlint)
+-- Copyright   :  (C) 2013 Edward Kmett
+-- License     :  BSD-style (see the file LICENSE)
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+-- This module runs HLint on the lens source tree.
+-----------------------------------------------------------------------------
+module Main where
+
+import Control.Monad
+import Language.Haskell.HLint
+import System.Environment
+import System.Exit
+
+main :: IO ()
+main = do
+    args <- getArgs
+    hints <- hlint $ ["src", "--cross", "--hint=tests/HLint.hs" ] ++ args
+    unless (null hints) exitFailure
