diff --git a/MIT-LICENSE.txt b/MIT-LICENSE.txt
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--- /dev/null
+++ b/MIT-LICENSE.txt
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+Copyright (c) 2015 Ian Grant Jeffries
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
+OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/README.md b/README.md
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--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+# Summary
+
+[Jcase](https://github.com/seagreen/Jcase) library for Haskell.
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/hjcase.cabal b/hjcase.cabal
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--- /dev/null
+++ b/hjcase.cabal
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+name:                   hjcase
+version:                0.1.0.0
+synopsis:               Jcase library for Haskell
+homepage:               https://github.com/seagreen/hjcase
+license:                MIT
+license-file:           MIT-LICENSE.txt
+author:                 Ian Grant Jeffries
+maintainer:             ian@housejeffries.com
+category:               Data
+build-type:             Simple
+cabal-version:          >=1.10
+extra-source-files:     README.md
+
+library
+  hs-source-dirs:       src
+  exposed-modules:      Data.Jcase
+  default-language:     Haskell2010
+  default-extensions:   OverloadedStrings
+  other-extensions:     TemplateHaskell
+  ghc-options:          -Wall
+  build-depends:        aeson                >= 0.8  && < 0.9
+                      , base                 >= 4.7  && < 4.8
+                      , bytestring           >= 0.10 && < 0.11
+                      , HUnit                >= 1.2  && < 1.3
+                      , test-framework       >= 0.8  && < 0.9
+                      , test-framework-hunit >= 0.3  && < 0.4
+                      , text                 >= 1.2  && < 1.3
+                      , unordered-containers >= 0.2  && < 0.3
+                      , vector               >= 0.10 && < 0.11
+
+source-repository head
+  type:               git
+  location:           git://github.com/seagreen/hjcase.git
diff --git a/src/Data/Jcase.hs b/src/Data/Jcase.hs
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--- /dev/null
+++ b/src/Data/Jcase.hs
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+{-# LANGUAGE TemplateHaskell #-}
+
+module Data.Jcase where
+
+import           Control.Monad
+import           Data.Aeson
+import           Data.Aeson.TH
+import qualified Data.ByteString.Lazy           as B
+import           Data.Char                      (toLower)
+import           Data.Foldable
+import           Data.Maybe
+import           Data.Monoid
+import           Data.Text                      (Text)
+import qualified Data.Text                      as T
+import qualified Data.Text.IO                   as TIO
+import           Data.Vector                    (Vector)
+import           Test.Framework                 (Test)
+import           Test.Framework.Providers.HUnit (testCase)
+import qualified Test.HUnit                     as HU
+
+data Jcase = Jcase
+  { _jcDescription :: Maybe Text
+  , _jcData        :: Maybe Value
+  , _jcAssertions  :: Vector JcaseAssertion
+  } deriving (Eq, Show)
+
+data JcaseAssertion = JcaseAssertion
+  { _description :: Maybe Text
+  , _input       :: Value
+  , _output      :: Value
+  } deriving (Eq, Show)
+
+jcaseToHUnit :: (Maybe Value -> Value -> Value) -> Jcase -> Test
+jcaseToHUnit f jc = do
+  let desc = T.unpack $ fromMaybe "" (_jcDescription jc)
+  testCase desc (traverse_ g $ _jcAssertions jc)
+  where
+    g :: JcaseAssertion -> HU.Assertion
+    g ja = do
+      let str = T.unpack $ fromMaybe "" (_description ja)
+      HU.assertEqual str
+        (_output ja) $
+        f (_jcData jc) (_input ja)
+
+stdinJcase :: (Maybe Value -> Value -> Value) -> IO ()
+stdinJcase f = do
+  b <- B.getContents
+  case eitherDecode b of
+    Left e   -> error e
+    Right jc -> do
+      traverse_ (g $ _jcData jc) (_jcAssertions jc)
+      TIO.putStrLn "Success"
+  where
+    g :: Maybe Value -> JcaseAssertion -> IO ()
+    g maybeData ja = do
+      let actual = f maybeData (_input ja)
+      unless (actual == _output ja) $ error (msg ja actual)
+
+    msg :: JcaseAssertion -> Value -> String
+    msg ja v =
+      let desc = T.unpack $ fromMaybe "" (_description ja)
+      in unlines $ (if null desc then [] else [desc]) <>
+        [ "expected: " <> show (_output ja)
+        , "but got: "  <> show v
+        ]
+
+$(deriveFromJSON defaultOptions { fieldLabelModifier = map toLower . drop 3 } ''Jcase)
+$(deriveFromJSON defaultOptions { fieldLabelModifier = drop 1 } ''JcaseAssertion)