diff --git a/app/App/Commands/Build.hs b/app/App/Commands/Build.hs
--- a/app/App/Commands/Build.hs
+++ b/app/App/Commands/Build.hs
@@ -17,7 +17,6 @@
 
 import qualified App.Commands.Options.Type                            as Z
 import qualified HaskellWorks.Data.RankSelect.CsPoppy                 as CS
-import qualified HaskellWorks.Data.RankSelect.CsPoppy.Internal.Alpha0 as A0
 import qualified HaskellWorks.Data.RankSelect.CsPoppy.Internal.Alpha1 as A1
 import qualified HaskellWorks.Data.RankSelect.Poppy512                as P512
 
diff --git a/hw-rankselect.cabal b/hw-rankselect.cabal
--- a/hw-rankselect.cabal
+++ b/hw-rankselect.cabal
@@ -1,7 +1,7 @@
 cabal-version:  2.2
 
 name:           hw-rankselect
-version:        0.13.1.0
+version:        0.13.2.0
 synopsis:       Rank-select
 description:    Please see README.md
 category:       Data, Bit, Succinct Data Structures, Data Structures
@@ -38,8 +38,8 @@
 common directory            { build-depends: directory            >= 1.2        && < 1.5    }
 common generic-lens         { build-depends: generic-lens         >= 1.0.0.0    && < 1.2    }
 common hedgehog             { build-depends: hedgehog             >= 1.0        && < 1.1    }
-common hspec                { build-depends: hspec                >= 2.4        && < 2.6    }
-common hw-balancedparens    { build-depends: hw-balancedparens    >= 0.2.2.0    && < 0.3    }
+common hspec                { build-depends: hspec                >= 2.4        && < 3      }
+common hw-balancedparens    { build-depends: hw-balancedparens    >= 0.2.2.0    && < 0.4    }
 common hw-bits              { build-depends: hw-bits              >= 0.4.0.0    && < 0.8    }
 common hw-fingertree        { build-depends: hw-fingertree        >= 0.1.1.0    && < 1.2    }
 common hw-hedgehog          { build-depends: hw-hedgehog          >= 0.1.0.1    && < 0.2    }
diff --git a/test/HaskellWorks/Data/RankSelect/BitSeqSpec.hs b/test/HaskellWorks/Data/RankSelect/BitSeqSpec.hs
--- a/test/HaskellWorks/Data/RankSelect/BitSeqSpec.hs
+++ b/test/HaskellWorks/Data/RankSelect/BitSeqSpec.hs
@@ -98,22 +98,49 @@
     ps        <- forAll $ pure $ BS.fromBools bs
 
     BS.toBools (ps |> b) === BS.toBools ps <> [b]
-  it "select1" $ requireTest $ do
-    n         <- forAll $ G.count (R.linear 0 1000)
-    bools     <- forAll $ G.list (R.singleton (fromIntegral n)) G.bool
-    bs        <- forAll $ pure $ BS.fromBools bools
-    i         <- forAll $ G.count (R.linear 0 n)
+  describe "one bitseq" $ do
+    it "select1" $ requireTest $ do
+      n         <- forAll $ G.count (R.linear 0 1000)
+      bools     <- forAll $ G.list (R.singleton (fromIntegral n)) G.bool
+      bs        <- forAll $ pure $ BS.fromBools bools
+      i         <- forAll $ G.count (R.linear 0 n)
 
-    select1 bools i === select1 bs i
-  it "rank1" $ requireTest $ do
-    n         <- forAll $ G.count (R.linear 0 1000)
-    bools     <- forAll $ G.list (R.singleton (fromIntegral n)) G.bool
-    bs        <- forAll $ pure $ BS.fromBools bools
-    i         <- forAll $ G.count (R.linear 0 (popCount1 bools))
+      select1 bools i === select1 bs i
+    it "rank1" $ requireTest $ do
+      n         <- forAll $ G.count (R.linear 0 1000)
+      bools     <- forAll $ G.list (R.singleton (fromIntegral n)) G.bool
+      bs        <- forAll $ pure $ BS.fromBools bools
+      i         <- forAll $ G.count (R.linear 0 (popCount1 bools))
 
-    rank1 bools i === rank1 bs i
-  it "popCount1" $ requireTest $ do
-    bools     <- forAll $ G.list (R.linear 0 1000) G.bool
-    bs        <- forAll $ pure $ BS.fromBools bools
+      rank1 bools i === rank1 bs i
+    it "popCount1" $ requireTest $ do
+      bools     <- forAll $ G.list (R.linear 0 1000) G.bool
+      bs        <- forAll $ pure $ BS.fromBools bools
 
-    popCount1 bools === popCount1 bs
+      popCount1 bools === popCount1 bs
+  describe "concatenated bitseq" $ do
+    it "select1" $ requireTest $ do
+      n         <- forAll $ G.count (R.linear 0 1000)
+      bools1    <- forAll $ G.list (R.singleton (fromIntegral n)) G.bool
+      bools2    <- forAll $ G.list (R.singleton (fromIntegral n)) G.bool
+      bs1       <- forAll $ pure $ BS.fromBools bools1
+      bs2       <- forAll $ pure $ BS.fromBools bools2
+      i         <- forAll $ G.count (R.linear 0 n)
+
+      select1 (bools1 <> bools2) i === select1 (bs1 <> bs2) i
+    it "rank1" $ requireTest $ do
+      n         <- forAll $ G.count (R.linear 0 1000)
+      bools1    <- forAll $ G.list (R.singleton (fromIntegral n)) G.bool
+      bools2    <- forAll $ G.list (R.singleton (fromIntegral n)) G.bool
+      bs1       <- forAll $ pure $ BS.fromBools bools1
+      bs2       <- forAll $ pure $ BS.fromBools bools2
+      i         <- forAll $ G.count (R.linear 0 (popCount1 (bools1 <> bools2)))
+
+      rank1 (bools1 <> bools2) i === rank1 (bs1 <> bs2) i
+    it "popCount1" $ requireTest $ do
+      bools1    <- forAll $ G.list (R.linear 0 1000) G.bool
+      bools2    <- forAll $ G.list (R.linear 0 1000) G.bool
+      bs1       <- forAll $ pure $ BS.fromBools bools1
+      bs2       <- forAll $ pure $ BS.fromBools bools2
+
+      popCount1 (bools1 <> bools2) === popCount1 (bs1 <> bs2)