Small refactor around error responses and more tests (#1282)

* Fix #880, Clean and consolidate error responses
* Fix #1285, Abort on fatal errors
* Add / Detail tests

test/Feature/RangeSpec.hs

@@ -38,7 +38,6 @@ spec = do
             { matchHeaders = ["Content-Range" <:> "0-14/*"] }
 
     context "with range headers" $ do
-
       context "of acceptable range" $ do
         it "succeeds with partial content" $ do
           r <- request methodPost  "/rpc/getitemrange"
@@ -156,7 +155,6 @@ spec = do
           , matchHeaders = ["Content-Range" <:> "0-0/*"]
           }
 
-
       it "limit and offset works on first level" $
         get "/items?select=id&order=id.asc&limit=3&offset=2"
           `shouldRespondWith` [json|[{"id":3},{"id":4},{"id":5}]|]
@@ -164,8 +162,37 @@ spec = do
           , matchHeaders = ["Content-Range" <:> "2-4/*"]
           }
 
-    context "with range headers" $ do
+      it "succeeds if offset equals 0 as a no-op" $
+        get "/items?select=id&offset=0"
+          `shouldRespondWith`
+          [json|[{"id":1},{"id":2},{"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}]|]
+          { matchStatus  = 200
+          , matchHeaders = ["Content-Range" <:> "0-14/*"]
+          }
 
+      it "succeeds if offset is negative as a no-op" $
+        get "/items?select=id&offset=-4"
+          `shouldRespondWith`
+          [json|[{"id":1},{"id":2},{"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}]|]
+          { matchStatus  = 200
+          , matchHeaders = ["Content-Range" <:> "0-14/*"]
+          }
+
+      it "fails if limit equals 0" $
+        get "/items?select=id&limit=0"
+          `shouldRespondWith` [json|{"message":"HTTP Range error"}|]
+          { matchStatus  = 416
+          , matchHeaders = [matchContentTypeJson]
+          }
+
+      it "fails if limit is negative" $
+        get "/items?select=id&limit=-1"
+          `shouldRespondWith` [json|{"message":"HTTP Range error"}|]
+          { matchStatus  = 416
+          , matchHeaders = [matchContentTypeJson]
+          }
+
+    context "with range headers" $ do
       context "of acceptable range" $ do
         it "succeeds with partial content" $ do
           r <- request methodGet  "/items"