diff --git a/Git/Smoke.hs b/Git/Smoke.hs
--- a/Git/Smoke.hs
+++ b/Git/Smoke.hs
@@ -10,14 +10,11 @@
 
 module Git.Smoke where
 
+import           Conduit
 import           Control.Applicative
 import           Control.Exception
 import           Control.Monad
-import           Control.Monad.IO.Class
-import           Control.Monad.Trans.Class
-import           Control.Monad.Trans.Control
 import qualified Data.ByteString.Lazy as BL
-import qualified Data.Conduit.Binary as CB
 import           Data.List (sort)
 import           Data.Monoid
 import           Data.Tagged
@@ -36,22 +33,33 @@
 sampleCommit tr sig =
     createCommit [] tr sig sig "Sample log message.\n" Nothing
 
-smokeTestSpec :: (MonadGit r m, MonadIO m, MonadBaseControl IO m,
-                  MonadGit s n, MonadIO n, MonadBaseControl IO n)
+smokeTestSpec :: (MonadGit r m, MonadIO m, MonadBaseControl IO m, MonadThrow m,
+                  MonadGit s n, MonadIO n, MonadBaseControl IO n, MonadThrow n)
               => RepositoryFactory m IO r
               -> RepositoryFactory n m s
               -> Spec
 smokeTestSpec pr _pr2 = describe "Smoke tests" $ do
-  it "create a single blob" $ withNewRepository pr "singleBlob.git" $ do
-      createBlobUtf8 "Hello, world!\n"
+  it "hash without persisting" $ withNewRepository pr "hashObject.git" $ do
+      r <- hashContents $ BlobString "flim-flam"
+      liftIO $ renderObjOid r @?= "5cc144cc0c3c101342b3f0c546c014d1e0e66da9"
 
-      x <- catBlob =<< parseObjOid "af5626b4a114abcb82d63db7c8082c3c4756e51b"
-      liftIO $ x @?= "Hello, world!\n"
+  -- it "create a single blob" $ withNewRepository pr "singleBlob.git" $ do
+  --     createBlobUtf8 "Hello, world!\n"
 
-      -- jww (2013-02-01): Restore when S3 support prefix lookups
-      -- x <- catBlob "af5626b"
-      -- liftIO $ x @?= "Hello, world!\n"
+  --     oid <- parseObjOid "af5626b4a114abcb82d63db7c8082c3c4756e51b"
+  --     x <- catBlob oid
+  --     liftIO $ x @?= "Hello, world!\n"
 
+  --     e1 <- existsObject $ untag oid
+  --     liftIO $ e1 @? "Expected object doesn't exist."
+
+  --     e2 <- existsObject =<< parseOid "efefefefefefefefefefefefefefefefefefefef"
+  --     liftIO $ not e2 @? "Unexpected object exists."
+
+  --     -- jww (2013-02-01): Restore when S3 support prefix lookups
+  --     -- x <- catBlob "af5626b"
+  --     -- liftIO $ x @?= "Hello, world!\n"
+
   it "create a single tree" $ withNewRepository pr "singleTree.git" $ do
       hello <- createBlobUtf8 "Hello, world!\n"
       tr <- createTree $ putBlob "hello/world.txt" hello
@@ -118,6 +126,31 @@
       let x = renderObjOid (commitOid c)
       liftIO $ x @?= "4e0529eb30f53e65c1e13836e73023c9d23c25ae"
 
+  -- it "tag a single commit" $ withNewRepository pr "tagCommit.git" $ do
+  --     hello <- createBlobUtf8 "Hello, world!\n"
+  --     tr <- createTree $ putBlob "hello/world.txt" hello
+
+  --     goodbye <- createBlobUtf8 "Goodbye, world!\n"
+  --     tr <- mutateTreeOid tr $ putBlob "goodbye/files/world.txt" goodbye
+  --     let x = renderObjOid tr
+  --     liftIO $ x @?= "98c3f387f63c08e1ea1019121d623366ff04de7a"
+
+  --     -- The Oid has been cleared in tr, so this tests that it gets
+  --     -- written as needed.
+  --     let sig  = Signature {
+  --             signatureName  = "John Wiegley"
+  --           , signatureEmail = "johnw@fpcomplete.com"
+  --           , signatureWhen  = fakeTime 1348980883 }
+
+  --     c <- commitOid <$> sampleCommit tr sig
+  --     t <- tagOid <$> createTag c sig "good" "name"
+  --     let x = renderObjOid t
+  --     liftIO $ x @?= "f2e15fe8138a30f663007005c59ab40e55857e24"
+
+  --     Tag ti ci <- lookupTag t
+  --     liftIO $ ti @?= t
+  --     liftIO $ ci @?= c
+
   it "modify a commit" $ withNewRepository pr "modifyCommit.git" $ do
       hello <- createBlobUtf8 "Hello, world!\n"
       tr <- createTree $ putBlob "hello/world.txt" hello
@@ -195,6 +228,9 @@
       refs <- listReferences
       liftIO $ show refs @?= "[\"refs/heads/master\"]"
 
+      deleteReference "refs/heads/master"
+      deleteReference "HEAD"
+
       -- jww (2013-01-27): Restore
       -- ehist <- commitHistoryFirstParent c2
       -- Prelude.putStrLn $ "ehist: " ++ show ehist
@@ -391,7 +427,7 @@
 mkBlob :: MonadGit r m => TreeFilePath -> TreeT r m ()
 mkBlob path = putBlob path
     =<< lift (createBlob $ BlobStream $
-                  CB.sourceLbs (BL.fromChunks [path <> "\n"]))
+                  sourceLazy (BL.fromChunks [path <> "\n"]))
 
 doTreeit :: (MonadBaseControl IO m, MonadIO m,
              MonadGit r n, MonadBaseControl IO n, MonadIO n)
diff --git a/gitlib-test.cabal b/gitlib-test.cabal
--- a/gitlib-test.cabal
+++ b/gitlib-test.cabal
@@ -1,5 +1,5 @@
 Name:                gitlib-test
-Version:             3.0.1
+Version:             3.1.0
 Synopsis:            Test library for confirming gitlib backend compliance
 License-file:        LICENSE
 License:             MIT
@@ -26,8 +26,9 @@
         , hspec                >= 1.4.4
         , hspec-expectations   >= 0.3
         , bytestring
-        , failure              >= 0.2.0
-        , conduit
+        , exceptions           >= 0.5
+        , conduit              >= 1.1.0
+        , conduit-combinators  >= 0.2.4
         , monad-control        >= 0.3.1
         , tagged               >= 0.4.4
         , text                 >= 0.11.2