adding tests.

test/LangSpec.hs

@@ -0,0 +1,14 @@
+module LangSpec where
+
+import Control.Applicative
+import Test.Hspec
+import Expectation
+import Lang
+import Types
+
+spec :: Spec
+spec = do
+    describe "listLanguages" $ do
+        it "lists up language extensions" $ do
+            modules <- lines <$> listLanguages defaultOptions
+            modules `shouldContain` "OverloadedStrings"