diff --git a/app/App/Commands.hs b/app/App/Commands.hs
--- a/app/App/Commands.hs
+++ b/app/App/Commands.hs
@@ -6,7 +6,6 @@
 import App.Commands.SelectedByBits
 import App.Commands.Slice
 import App.Commands.Words
-import Data.Semigroup              ((<>))
 import Options.Applicative
 
 cmdOpts :: Parser (IO ())
diff --git a/app/App/Commands/Bits.hs b/app/App/Commands/Bits.hs
--- a/app/App/Commands/Bits.hs
+++ b/app/App/Commands/Bits.hs
@@ -8,7 +8,6 @@
 
 import Control.Lens
 import Data.Generics.Product.Any
-import Data.Semigroup                 ((<>))
 import HaskellWorks.Data.Bits.BitShow
 import HaskellWorks.Data.Positioning
 import Options.Applicative            hiding (columns)
diff --git a/app/App/Commands/Complement.hs b/app/App/Commands/Complement.hs
--- a/app/App/Commands/Complement.hs
+++ b/app/App/Commands/Complement.hs
@@ -8,7 +8,6 @@
 
 import Control.Lens
 import Data.Generics.Product.Any
-import Data.Semigroup                 ((<>))
 import HaskellWorks.Data.Bits.BitWise
 import Options.Applicative            hiding (columns)
 
diff --git a/app/App/Commands/InterestBits.hs b/app/App/Commands/InterestBits.hs
--- a/app/App/Commands/InterestBits.hs
+++ b/app/App/Commands/InterestBits.hs
@@ -11,7 +11,6 @@
 import Data.Char                      (isAscii, isPrint)
 import Data.Generics.Product.Any
 import Data.List                      (transpose)
-import Data.Semigroup                 ((<>))
 import HaskellWorks.Data.Bits.BitShow
 import Numeric                        (showHex)
 import Options.Applicative            hiding (columns)
diff --git a/app/App/Commands/SelectedByBits.hs b/app/App/Commands/SelectedByBits.hs
--- a/app/App/Commands/SelectedByBits.hs
+++ b/app/App/Commands/SelectedByBits.hs
@@ -10,7 +10,6 @@
 import Control.Monad
 import Data.Bits                      (countTrailingZeros)
 import Data.Generics.Product.Any
-import Data.Semigroup                 ((<>))
 import Data.Word
 import HaskellWorks.Data.Bits.BitWise
 import Options.Applicative            hiding (columns)
diff --git a/app/App/Commands/Slice.hs b/app/App/Commands/Slice.hs
--- a/app/App/Commands/Slice.hs
+++ b/app/App/Commands/Slice.hs
@@ -10,7 +10,6 @@
 import Control.Monad
 import Data.Bits.Pext
 import Data.Generics.Product.Any
-import Data.Semigroup                      ((<>))
 import Data.Word
 import HaskellWorks.Data.Vector.AsVector64
 import Options.Applicative                 hiding (columns)
diff --git a/app/App/Commands/Words.hs b/app/App/Commands/Words.hs
--- a/app/App/Commands/Words.hs
+++ b/app/App/Commands/Words.hs
@@ -9,7 +9,6 @@
 import Control.Lens
 import Control.Monad
 import Data.Generics.Product.Any
-import Data.Semigroup            ((<>))
 import Data.Word
 import Numeric                   (showHex)
 import Options.Applicative       hiding (columns)
diff --git a/app/Main.hs b/app/Main.hs
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -2,7 +2,6 @@
 
 import App.Commands
 import Control.Monad
-import Data.Semigroup      ((<>))
 import Options.Applicative
 
 main :: IO ()
diff --git a/doctest/DoctestDriver.hs b/doctest/DoctestDriver.hs
new file mode 100644
--- /dev/null
+++ b/doctest/DoctestDriver.hs
@@ -0,0 +1,12 @@
+{-# LANGUAGE CPP #-}
+
+#if MIN_VERSION_GLASGOW_HASKELL(8,4,4,0)
+{-# OPTIONS_GHC -F -pgmF doctest-discover #-}
+#else
+module Main where
+
+import qualified System.IO as IO
+
+main :: IO ()
+main = IO.putStrLn "WARNING: doctest will not run on GHC versions earlier than 8.4.4"
+#endif
diff --git a/hw-dump.cabal b/hw-dump.cabal
--- a/hw-dump.cabal
+++ b/hw-dump.cabal
@@ -1,22 +1,21 @@
-cabal-version:        2.2
+cabal-version: 2.2
 
-name:                 hw-dump
-version:              0.1.0.1
-synopsis:             File Dump
-description:          Please see README.md
-category:             Data, Bit
-stability:            Experimental
-homepage:             http://github.com/haskell-works/hw-dump#readme
-bug-reports:          https://github.com/haskell-works/hw-dump/issues
-author:               John Ky
-maintainer:           newhoggy@gmail.com
-copyright:            2016-2019 John Ky
-license:              BSD-3-Clause
-license-file:         LICENSE
-tested-with:          GHC == 8.8.1, GHC == 8.6.5, GHC == 8.4.4, GHC == 8.2.2
-build-type:           Simple
-extra-source-files:
-  README.md
+name:                   hw-dump
+version:                0.1.1.0
+synopsis:               File Dump
+description:            Please see README.md
+category:               Data, Bit
+stability:              Experimental
+homepage:               http://github.com/haskell-works/hw-dump#readme
+bug-reports:            https://github.com/haskell-works/hw-dump/issues
+author:                 John Ky
+maintainer:             newhoggy@gmail.com
+copyright:              2016-2020 John Ky
+license:                BSD-3-Clause
+license-file:           LICENSE
+tested-with:            GHC == 8.10.1, GHC == 8.8.3, GHC == 8.6.5, GHC == 8.4.4
+build-type:             Simple
+extra-source-files:     README.md
 
 source-repository head
   type: git
@@ -27,22 +26,24 @@
   manual: False
   default: True
 
-common base                 { build-depends: base                 >= 4          && < 5      }
+common base                       { build-depends: base                       >= 4.11       && < 5      }
 
-common bits-extra           { build-depends: bits-extra           >= 0.0.1.3    && < 0.1    }
-common bytestring           { build-depends: bytestring           >= 0.9        && < 0.11   }
-common criterion            { build-depends: criterion            >= 1.2        && < 1.6    }
-common generic-lens         { build-depends: generic-lens         >= 1.2.0.0    && < 1.3    }
-common hedgehog             { build-depends: hedgehog             >= 0.6        && < 1.1    }
-common hspec                { build-depends: hspec                >= 2.4        && < 3.0    }
-common hw-bits              { build-depends: hw-bits              >= 0.7.0.3    && < 0.8    }
-common hw-hspec-hedgehog    { build-depends: hw-hspec-hedgehog    >= 0.1        && < 0.2    }
-common hw-prim              { build-depends: hw-prim              >= 0.6.2.19   && < 0.7    }
-common lens                 { build-depends: lens                 >= 4          && < 5      }
-common optparse-applicative { build-depends: optparse-applicative >= 0.14       && < 0.16   }
-common QuickCheck           { build-depends: QuickCheck           >= 2.10       && < 2.14   }
-common safe                 { build-depends: safe                 >= 0.2        && < 0.4    }
-common vector               { build-depends: vector               >= 0.12       && < 0.13   }
+common bits-extra                 { build-depends: bits-extra                 >= 0.0.1.3    && < 0.1    }
+common bytestring                 { build-depends: bytestring                 >= 0.9        && < 0.11   }
+common criterion                  { build-depends: criterion                  >= 1.2        && < 1.6    }
+common doctest                    { build-depends: doctest                    >= 0.16.2     && < 0.17   }
+common doctest-discover           { build-depends: doctest-discover           >= 0.2        && < 0.3    }
+common generic-lens               { build-depends: generic-lens               >= 1.2.0.0    && < 1.3    }
+common hedgehog                   { build-depends: hedgehog                   >= 0.6        && < 1.1    }
+common hspec                      { build-depends: hspec                      >= 2.4        && < 3.0    }
+common hw-bits                    { build-depends: hw-bits                    >= 0.7.0.3    && < 0.8    }
+common hw-hspec-hedgehog          { build-depends: hw-hspec-hedgehog          >= 0.1        && < 0.2    }
+common hw-prim                    { build-depends: hw-prim                    >= 0.6.2.19   && < 0.7    }
+common lens                       { build-depends: lens                       >= 4          && < 5      }
+common optparse-applicative       { build-depends: optparse-applicative       >= 0.14       && < 0.16   }
+common QuickCheck                 { build-depends: QuickCheck                 >= 2.10       && < 2.15   }
+common safe                       { build-depends: safe                       >= 0.2        && < 0.4    }
+common vector                     { build-depends: vector                     >= 0.12       && < 0.13   }
 
 common config
   default-language:     Haskell2010
@@ -50,63 +51,63 @@
   if flag(sse42)
     ghc-options: -msse4.2
 
+common hw-dump
+  build-depends:        hw-dump
+
 library
-  import:   base, config
-          , bits-extra
-          , bytestring
-          , hw-bits
-          , hw-prim
-          , safe
-          , vector
-  exposed-modules:
-    HaskellWorks.Data.Dump
+  import:               base, config
+                      , bits-extra
+                      , bytestring
+                      , hw-bits
+                      , hw-prim
+                      , safe
+                      , vector
+  exposed-modules:      HaskellWorks.Data.Dump
   other-modules:        Paths_hw_dump
   autogen-modules:      Paths_hw_dump
   hs-source-dirs:       src
 
 executable hw-dump
-  import:   base, config
-          , bits-extra
-          , bytestring
-          , generic-lens
-          , hw-bits
-          , hw-prim
-          , lens
-          , optparse-applicative
-          , vector
+  import:               base, config
+                      , bits-extra
+                      , bytestring
+                      , generic-lens
+                      , hw-bits
+                      , hw-prim
+                      , lens
+                      , optparse-applicative
+                      , vector
   main-is:              Main.hs
   hs-source-dirs:       app
   ghc-options:          -threaded -rtsopts -with-rtsopts=-N
-  other-modules:
-    App.Commands
-    App.Commands.Bits
-    App.Commands.Complement
-    App.Commands.InterestBits
-    App.Commands.Options.Type
-    App.Commands.SelectedByBits
-    App.Commands.Slice
-    App.Commands.Words
-    Paths_hw_dump
+  other-modules:        App.Commands
+                        App.Commands.Bits
+                        App.Commands.Complement
+                        App.Commands.InterestBits
+                        App.Commands.Options.Type
+                        App.Commands.SelectedByBits
+                        App.Commands.Slice
+                        App.Commands.Words
+                        Paths_hw_dump
 
 test-suite hw-dump-test
-  import:   base, config
-          , QuickCheck
-          , bits-extra
-          , bytestring
-          , hedgehog
-          , hspec
-          , hw-bits
-          , hw-hspec-hedgehog
-          , hw-prim
-          , vector
+  import:               base, config
+                      , QuickCheck
+                      , bits-extra
+                      , bytestring
+                      , hedgehog
+                      , hspec
+                      , hw-bits
+                      , hw-hspec-hedgehog
+                      , hw-prim
+                      , vector
   type:                 exitcode-stdio-1.0
   main-is:              Spec.hs
   hs-source-dirs:       test
   ghc-options:          -threaded -rtsopts -with-rtsopts=-N -Wall
   build-tool-depends:   hspec-discover:hspec-discover
-  other-modules:
-      HaskellWorks.Data.Dump.DumpSpec
-      Paths_hw_dump
+  other-modules:        HaskellWorks.Data.Dump.DumpSpec
+                        Paths_hw_dump
 
 benchmark bench
   import:   base, config
@@ -120,4 +121,15 @@
   main-is:              Main.hs
   other-modules:        Paths_hw_dump
   hs-source-dirs:       bench
-  build-depends:
+
+test-suite doctest
+  import:               base, config
+                      , doctest
+                      , doctest-discover
+                      , hw-dump
+  default-language:     Haskell2010
+  type:                 exitcode-stdio-1.0
+  ghc-options:          -threaded
+  main-is:              DoctestDriver.hs
+  HS-Source-Dirs:       doctest
+  build-tool-depends:   doctest-discover:doctest-discover
