Handle overloaded function case

* Add test for params=single-object on GET

* Add tests for procs with DEFAULT args

* Add tests for overloaded functions

* Add test for PATCHing with an empty json array, this previously
  gave a "Something is wrong" error

test/Feature/InsertSpec.hs

@@ -416,13 +416,21 @@ spec = do
         -- put value back for other tests
         void $ request methodPatch "/items?id=eq.99" [] [json| { "id":1 } |]
 
-      it "makes no updates and returns 204, when patching with an empty json object" $ do
+      it "makes no updates and returns 204, when patching with an empty json object/array" $ do
         request methodPatch "/items" [] [json| {} |]
           `shouldRespondWith` ""
           {
             matchStatus  = 204,
             matchHeaders = ["Content-Range" <:> "*/*"]
           }
+
+        request methodPatch "/items" [] [json| [] |]
+          `shouldRespondWith` ""
+          {
+            matchStatus  = 204,
+            matchHeaders = ["Content-Range" <:> "*/*"]
+          }
+
         get "/items" `shouldRespondWith`
           [json|[{"id":3},{"id":4},{"id":5},{"id":6},{"id":7},{"id":8},{"id":9},{"id":10},{"id":11},{"id":12},{"id":13},{"id":14},{"id":15},{id:16},{"id":2},{"id":1}]|]
           { matchHeaders = [matchContentTypeJson] }