diff --git a/amazonka-test.cabal b/amazonka-test.cabal
--- a/amazonka-test.cabal
+++ b/amazonka-test.cabal
@@ -1,5 +1,5 @@
 name:                  amazonka-test
-version:               1.4.4.2
+version:               1.4.5
 synopsis:              Common functionality for Amazonka library test-suites.
 homepage:              https://github.com/brendanhay/amazonka
 bug-reports:           https://github.com/brendanhay/amazonka/issues
@@ -37,7 +37,7 @@
 
     build-depends:
           aeson                >= 0.8
-        , amazonka-core        == 1.4.4.*
+        , amazonka-core        == 1.4.5.*
         , base                 >= 4.7     && < 5
         , bifunctors           >= 4.1
         , bytestring           >= 0.9
diff --git a/src/Test/AWS/Fixture.hs b/src/Test/AWS/Fixture.hs
--- a/src/Test/AWS/Fixture.hs
+++ b/src/Test/AWS/Fixture.hs
@@ -32,6 +32,7 @@
 import           Data.Time
 import qualified Data.Yaml                    as YAML
 import           Network.AWS.Data.ByteString
+import qualified Network.AWS.Data.Map         as Map
 import           Network.AWS.Lens             (trying, (<&>))
 import           Network.AWS.Prelude
 import           Network.HTTP.Client.Internal hiding (Proxy, Request, Response)
@@ -123,7 +124,7 @@
         <$> o .: "method"
         <*> (o .:? "path"    .!= "/")
         <*> (o .:? "query"   .!= mempty)
-        <*> (o .:? "headers" .!= mempty <&> Map.toList)
+        <*> (o .:? "headers" .!= mempty <&> Map.toList . Map.toMap)
         <*> (o .:? "body"    .!= mempty)
 
 sortKeys :: Ord a => [(a, b)] -> [(a, b)]
diff --git a/src/Test/AWS/Orphans.hs b/src/Test/AWS/Orphans.hs
--- a/src/Test/AWS/Orphans.hs
+++ b/src/Test/AWS/Orphans.hs
@@ -14,28 +14,8 @@
 --
 module Test.AWS.Orphans where
 
-import           Data.Aeson
-import qualified Data.CaseInsensitive as CI
-import qualified Data.HashMap.Strict  as Map
-import qualified Data.Text.Encoding   as Text
-import           Data.Traversable     (traverse)
-import           Network.AWS.Prelude
+import Data.Aeson
+import Network.AWS.Prelude
 
 instance FromJSON ByteString where
     parseJSON = withText "bytestring" (either fail pure . fromText)
-
-instance FromJSON (HashMap ByteString ByteString) where
-    parseJSON = withObject "hashmap" $
-          fmap Map.fromList
-        . traverse go
-        . Map.toList
-      where
-        go (k, v) = (Text.encodeUtf8 k,) <$> parseJSON v
-
-instance FromJSON (HashMap HeaderName ByteString) where
-    parseJSON = withObject "headers" $
-          fmap Map.fromList
-        . traverse go
-        . Map.toList
-      where
-        go (k, v) = (CI.mk (Text.encodeUtf8 k),) <$> parseJSON v