Add Content-Location header to GET responses

Fixes #26

test/Feature/QuerySpec.hs

@@ -0,0 +1,30 @@
+
+{-# LANGUAGE OverloadedStrings #-}
+module Feature.QuerySpec where
+
+import Test.Hspec
+import Test.Hspec.Wai
+
+import SpecHelper
+
+spec :: Spec
+spec = around appWithFixture $ do
+  describe "Filtering response" $
+    context "column equality" $
+
+      it "matches the predicate" $
+        get "/items?id=eq.5"
+          `shouldRespondWith` ResponseMatcher {
+            matchBody    = Just "[{\"id\":5}]"
+          , matchStatus  = 200
+          , matchHeaders = [("Content-Range", "0-0/1")]
+          }
+
+  describe "Canonical location" $
+    it "Sets Content-Location with alphabetized params" $
+      get "/no_pk?b=eq.1&a=eq.1"
+        `shouldRespondWith` ResponseMatcher {
+          matchBody    = Nothing
+        , matchStatus  = 204
+        , matchHeaders = [("Content-Location", "/no_pk?a=eq.1&b=eq.1")]
+        }