Add test for prepost (#629)

Author: kharus

lib/haskell/natural4/src/LS/XPile/AaJson.hs

@@ -72,7 +72,7 @@ import Data.Aeson.Encode.Pretty (encodePretty)
 
 labelToAaJson :: AA.Label T.Text -> Value
 labelToAaJson (AA.Pre a) = object [ "Pre" .= a ]
-labelToAaJson (AA.PrePost a b) = object [ "PrePost" .= [a,b] ]
+labelToAaJson (AA.PrePost a b) = object [ "Pre" .= a, "Post" .= b ]
 labelToAaJson (AA.Metadata a) = object [ "Metadata" .= a ]
 
 bsToAaJson :: BoolStructLT -> Value

lib/haskell/natural4/test/LS/XPile/AaJsonSpec.hs

@@ -114,3 +114,8 @@ spec = do
       it "convert must sing to AaJson" do
         rodents_purs <- transpileFile "rodents"
         pure $ goldenGeneric "rodents" rodents_purs
+    
+    describe "pdpa" do
+      it "convert must sing to AaJson" do
+        rodents_purs <- transpileFile "pdpa"
+        pure $ goldenGeneric "pdpa" rodents_purs