Test Suite in Cabal (cabal test)

Please run using "cabal test --show-details=streaming", there's a known
issue about this that was fixed in the latest version of cabal:
https://github.com/haskell/cabal/issues/1810

test/shellcheck.hs

@@ -0,0 +1,16 @@
+module Main where
+
+import Control.Monad
+import System.Exit
+import qualified ShellCheck.Simple
+import qualified ShellCheck.Analytics
+import qualified ShellCheck.Parser
+
+main = do
+    putStrLn "Running ShellCheck tests..."
+    results <- sequence [ShellCheck.Simple.runTests,
+                         ShellCheck.Analytics.runTests,
+                         ShellCheck.Parser.runTests]
+    if and results then exitSuccess
+     else exitFailure
+