added enum pretty printing tests

resources/Enums/haskellEnum1.hs

@@ -0,0 +1,13 @@
+{-The enumerated values to specified the period, e.g. day, week.-}
+data PeriodEnum =
+    {-Day-}
+    D
+    {-Month-}
+    | M
+    {-Year-}
+    | Y
+
+instance Show PeriodEnum where
+    show D = "day"
+    show M = "month"
+    show Y = "year"