X.U.EZConfig: Add simple unit tests

Add very basic unit tests for EZConfig to see if it can parse all of the
keys (and key combinations) that it promises to parse.

The long-term goal here should be to write a pretty-printer for EZConfig
and to check whether that's a proper inverse (either in the normal sense
or in the inverse semigroup sense), as the tests for X.P.OrgMode do.

XMonad/Util/EZConfig.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 --------------------------------------------------------------------
 -- |
 -- Module      :  XMonad.Util.EZConfig
@@ -34,7 +35,11 @@ module XMonad.Util.EZConfig (
 
                              parseKey, -- used by XMonad.Util.Paste
                              parseKeyCombo,
-                             parseKeySequence, readKeySequence
+                             parseKeySequence, readKeySequence,
+#ifdef TESTING
+                             functionKeys, specialKeys, multimediaKeys,
+                             parseModifier,
+#endif
                             ) where
 
 import XMonad