diff --git a/safe-coloured-text-gen.cabal b/safe-coloured-text-gen.cabal
new file mode 100644
--- /dev/null
+++ b/safe-coloured-text-gen.cabal
@@ -0,0 +1,57 @@
+cabal-version: 1.12
+
+-- This file has been generated from package.yaml by hpack version 0.34.4.
+--
+-- see: https://github.com/sol/hpack
+
+name:           safe-coloured-text-gen
+version:        0.0.0.0
+description:    Generators for types in safe-coloured-text
+homepage:       https://github.com/NorfairKing/safe-coloured-text#readme
+bug-reports:    https://github.com/NorfairKing/safe-coloured-text/issues
+author:         Tom Sydney Kerckhove
+maintainer:     syd@cs-syd.eu
+copyright:      Copyright (c) 2020 Tom Sydney Kerckhove
+license:        MIT
+build-type:     Simple
+
+source-repository head
+  type: git
+  location: https://github.com/NorfairKing/safe-coloured-text
+
+library
+  exposed-modules:
+      Text.Colour.Gen
+  other-modules:
+      Paths_safe_coloured_text_gen
+  hs-source-dirs:
+      src
+  build-depends:
+      base >=4.7 && <5
+    , genvalidity
+    , genvalidity-bytestring
+    , genvalidity-text
+    , safe-coloured-text
+  default-language: Haskell2010
+
+test-suite safe-coloured-text-test
+  type: exitcode-stdio-1.0
+  main-is: Spec.hs
+  other-modules:
+      Text.Colour.ChunkSpec
+      Text.Colour.CodeSpec
+      Text.ColourSpec
+      Paths_safe_coloured_text_gen
+  hs-source-dirs:
+      test
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N
+  build-tool-depends:
+      sydtest-discover:sydtest-discover
+  build-depends:
+      base >=4.7 && <5
+    , genvalidity-sydtest
+    , safe-coloured-text
+    , safe-coloured-text-gen
+    , sydtest
+    , text
+  default-language: Haskell2010
diff --git a/src/Text/Colour/Gen.hs b/src/Text/Colour/Gen.hs
new file mode 100644
--- /dev/null
+++ b/src/Text/Colour/Gen.hs
@@ -0,0 +1,45 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+
+module Text.Colour.Gen where
+
+import Data.GenValidity
+import Data.GenValidity.ByteString ()
+import Data.GenValidity.Text ()
+import Text.Colour
+import Text.Colour.Code
+
+instance GenValid Chunk where
+  genValid = genValidStructurallyWithoutExtraChecking
+  shrinkValid = shrinkValidStructurallyWithoutExtraFiltering
+
+instance GenValid CSI where
+  genValid = genValidStructurallyWithoutExtraChecking
+  shrinkValid = shrinkValidStructurallyWithoutExtraFiltering
+
+instance GenValid SGR where
+  genValid = genValidStructurallyWithoutExtraChecking
+  shrinkValid = shrinkValidStructurallyWithoutExtraFiltering
+
+instance GenValid Underlining where
+  genValid = genValidStructurallyWithoutExtraChecking
+  shrinkValid = shrinkValidStructurallyWithoutExtraFiltering
+
+instance GenValid ColourIntensity where
+  genValid = genValidStructurallyWithoutExtraChecking
+  shrinkValid = shrinkValidStructurallyWithoutExtraFiltering
+
+instance GenValid ConsoleIntensity where
+  genValid = genValidStructurallyWithoutExtraChecking
+  shrinkValid = shrinkValidStructurallyWithoutExtraFiltering
+
+instance GenValid ConsoleLayer where
+  genValid = genValidStructurallyWithoutExtraChecking
+  shrinkValid = shrinkValidStructurallyWithoutExtraFiltering
+
+instance GenValid TerminalColour where
+  genValid = genValidStructurallyWithoutExtraChecking
+  shrinkValid = shrinkValidStructurallyWithoutExtraFiltering
+
+instance GenValid Colour where
+  genValid = genValidStructurallyWithoutExtraChecking
+  shrinkValid = shrinkValidStructurallyWithoutExtraFiltering
diff --git a/test/Spec.hs b/test/Spec.hs
new file mode 100644
--- /dev/null
+++ b/test/Spec.hs
@@ -0,0 +1,1 @@
+{-# OPTIONS_GHC -F -pgmF sydtest-discover #-}
diff --git a/test/Text/Colour/ChunkSpec.hs b/test/Text/Colour/ChunkSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/Text/Colour/ChunkSpec.hs
@@ -0,0 +1,240 @@
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RecordWildCards #-}
+
+module Text.Colour.ChunkSpec (spec) where
+
+import Control.Monad
+import Data.Char as Char
+import Data.List
+import qualified Data.Text as T
+import Test.Syd
+import Text.Colour.Capabilities
+import Text.Colour.Chunk
+import Text.Colour.Code
+
+spec :: Spec
+spec = do
+  let gf = ("test_resources/chunk/" ++)
+  describe "renderChunk" $ do
+    it "outputs plain text if the terminal has no colours" $
+      renderChunksBS WithoutColours [fore red "hello"] `shouldBe` "hello"
+    it "outputs plain text if the terminal has no colours and 256 are needed" $
+      renderChunksBS WithoutColours [fore (colour256 128) "hello"] `shouldBe` "hello"
+    it "outputs plain text if the terminal has only 8 colours and 256 are needed" $
+      renderChunksBS With8Colours [fore (colour256 128) "hello"] `shouldBe` "hello"
+    it "outputs plain text if the terminal has no colours and 24bit colours are needed" $
+      renderChunksBS WithoutColours [fore (colourRGB 128 128 128) "hello"] `shouldBe` "hello"
+    it "outputs plain text if the terminal has only 8 colours and 24bit colours are needed" $
+      renderChunksBS With8Colours [fore (colourRGB 128 128 128) "hello"] `shouldBe` "hello"
+    it "outputs plain text if the terminal has only 8bit colours and 24bit colours are needed" $
+      renderChunksBS With8BitColours [fore (colourRGB 128 128 128) "hello"] `shouldBe` "hello"
+    it "outputs a plain chunk the same as before" $
+      pureGoldenByteStringFile (gf "plain.dat") (renderChunkBS With24BitColours (chunk "ook"))
+    describe "8 colours" $ do
+      let gf8 = ("test_resources/chunk/8/" ++)
+      let chunks string = justAFew $ do
+            let colour = do
+                  terminalColour <- [minBound .. maxBound]
+                  intensity <- [minBound .. maxBound]
+                  pure $ Colour8 intensity terminalColour
+            let mColour = Nothing : map Just colour
+            chunkItalic <- Nothing : map Just [minBound .. maxBound]
+            chunkConsoleIntensity <- Nothing : map Just [minBound .. maxBound]
+            chunkUnderlining <- Nothing : map Just [minBound .. maxBound]
+            chunkForeground <- mColour
+            chunkBackground <- mColour
+            let chunkText = T.pack string
+            let italicName i = if i then "non-italic" else "italic"
+                consoleIntensityName :: ConsoleIntensity -> String
+                consoleIntensityName = \case
+                  BoldIntensity -> "bold"
+                  FaintIntensity -> "faint"
+                  NormalIntensity -> "non-bold"
+                underliningName :: Underlining -> String
+                underliningName = \case
+                  SingleUnderline -> "underline"
+                  DoubleUnderline -> "double underline"
+                  NoUnderline -> "no underline"
+                name =
+                  unwords $
+                    filter
+                      (not . null)
+                      [ maybe "" italicName chunkItalic,
+                        maybe "" consoleIntensityName chunkConsoleIntensity,
+                        maybe "" underliningName chunkUnderlining,
+                        string,
+                        "with",
+                        mColourName chunkForeground,
+                        "foreground on",
+                        mColourName chunkBackground,
+                        "background"
+                      ]
+
+                italicPath i = if i then "non-italic" else "italic"
+                consoleIntensityPath :: ConsoleIntensity -> FilePath
+                consoleIntensityPath = \case
+                  BoldIntensity -> "bold"
+                  FaintIntensity -> "faint"
+                  NormalIntensity -> "non-bold"
+                underliningPath :: Underlining -> FilePath
+                underliningPath = \case
+                  SingleUnderline -> "underline"
+                  DoubleUnderline -> "double-underline"
+                  NoUnderline -> "no-underline"
+                path =
+                  intercalate
+                    "-"
+                    ( filter
+                        (not . null)
+                        [ maybe "" italicPath chunkItalic,
+                          maybe "" consoleIntensityPath chunkConsoleIntensity,
+                          maybe "" underliningPath chunkUnderlining,
+                          mColourPath chunkForeground,
+                          "fg",
+                          mColourPath chunkBackground,
+                          "bg"
+                        ]
+                    )
+                    <> ".dat"
+            pure (name, path, Chunk {..})
+
+      forM_ (chunks "ook") $ \(name, path, c) ->
+        it (unwords ["outputs a", name, "the same way as before"]) $
+          pureGoldenByteStringFile (gf8 path) (renderChunkBS With24BitColours c)
+    describe "8bit colours" $ do
+      let gf8bit = ("test_resources/chunk/8bit/" ++)
+      let chunks string = justAFew $ do
+            let colour = Colour8Bit <$> [minBound .. maxBound]
+            let mColour = Nothing : map Just colour
+            let chunkItalic = Nothing
+            let chunkConsoleIntensity = Nothing
+            let chunkUnderlining = Nothing
+            chunkForeground <- mColour
+            chunkBackground <- mColour
+            let chunkText = T.pack string
+            let name =
+                  unwords
+                    [ mColourName chunkForeground,
+                      "foreground on",
+                      mColourName chunkBackground,
+                      "background"
+                    ]
+                path =
+                  intercalate
+                    "-"
+                    [ mColourPath chunkForeground,
+                      "fg",
+                      mColourPath chunkBackground,
+                      "bg"
+                    ]
+                    <> ".dat"
+            pure (name, path, Chunk {..})
+
+      forM_ (chunks "ook") $ \(name, path, c) ->
+        it (unwords ["outputs a", name, "the same way as before"]) $
+          pureGoldenByteStringFile (gf8bit path) (renderChunkBS With24BitColours c)
+    describe "24bit colours" $ do
+      let gf24bit = ("test_resources/chunk/24bit/" ++)
+      let chunks string = justAFew $ do
+            let colour = do
+                  let w = [0, 16 .. 255] -- Just a few colours, otherwise we end up with a boatload of files.
+                  r <- w
+                  g <- w
+                  b <- w
+                  pure $ Colour24Bit r g b
+            let mColour = Nothing : map Just colour
+            let chunkItalic = Nothing
+            let chunkConsoleIntensity = Nothing
+            let chunkUnderlining = Nothing
+            chunkForeground <- mColour
+            chunkBackground <- mColour
+            let chunkText = T.pack string
+            let name =
+                  unwords
+                    [ mColourName chunkForeground,
+                      "foreground on",
+                      mColourName chunkBackground,
+                      "background"
+                    ]
+                path =
+                  intercalate
+                    "-"
+                    [ mColourPath chunkForeground,
+                      "fg",
+                      mColourPath chunkBackground,
+                      "bg"
+                    ]
+                    <> ".dat"
+            pure (name, path, Chunk {..})
+
+      forM_ (chunks "ook") $ \(name, path, c) ->
+        it (unwords ["outputs a", name, "the same way as before"]) $
+          pureGoldenByteStringFile (gf24bit path) (renderChunkBS With24BitColours c)
+    describe "super fancy" $ do
+      it "outputs this super fancy thing the same way as before" $
+        let bc c = back c $ chunk " "
+
+            colour8Bits = Colour8Bit <$> [16 .. maxBound]
+            colour8Bitss = (Colour8Bit <$> [0 .. 7]) : (Colour8Bit <$> [8 .. 15]) : chunksOf 36 colour8Bits
+            wsWithGaps = [0, 16 .. 255]
+            colour24Bits = (Colour24Bit <$> wsWithGaps <*> wsWithGaps <*> wsWithGaps)
+            colour24Bitss = chunksOf 64 colour24Bits
+            cs =
+              intercalate
+                ["\n"]
+                $ concat
+                  [ [ "Terminal colours (dull):   " : map (bc . Colour8 Dull) [minBound .. maxBound],
+                      "Terminal colours (bright): " : map (bc . Colour8 Bright) [minBound .. maxBound]
+                    ],
+                    ["\n8 bit colours:"] : map (map bc) colour8Bitss,
+                    ["\n24 bit colours:"] : map (map bc) colour24Bitss
+                  ]
+         in pureGoldenByteStringFile (gf "fancy.dat") (renderChunksBS With24BitColours cs)
+
+chunksOf :: Int -> [a] -> [[a]]
+chunksOf w l
+  | length l > w = take w l : chunksOf w (drop w l)
+  | otherwise = [l]
+
+colourName :: Colour -> String
+colourName =
+  unwords . \case
+    Colour8 intensity terminalColour ->
+      [ show intensity,
+        show terminalColour
+      ]
+    Colour8Bit w ->
+      [ "8-bit colour",
+        show w
+      ]
+    Colour24Bit r g b ->
+      [ "8-bit colour",
+        show (r, g, b)
+      ]
+
+mColourName :: Maybe Colour -> String
+mColourName Nothing = "no"
+mColourName (Just c) = "a(n) " <> colourName c
+
+colourPath :: Colour -> FilePath
+colourPath =
+  map Char.toLower
+    . intercalate "-"
+    . \case
+      Colour8 intensity terminalColour ->
+        [ show intensity,
+          show terminalColour
+        ]
+      Colour8Bit w -> [show w]
+      Colour24Bit r g b -> [show r, show g, show b]
+
+mColourPath :: Maybe Colour -> FilePath
+mColourPath Nothing = "no"
+mColourPath (Just c) = colourPath c
+
+justAFew :: [a] -> [a]
+justAFew = go 1
+  where
+    go _ [] = []
+    go i (a : as) = a : go (2 * i) (drop i as)
diff --git a/test/Text/Colour/CodeSpec.hs b/test/Text/Colour/CodeSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/Text/Colour/CodeSpec.hs
@@ -0,0 +1,66 @@
+module Text.Colour.CodeSpec (spec) where
+
+import Control.Monad
+import Data.Char as Char
+import Data.List
+import Test.Syd
+import Text.Colour.Code
+
+spec :: Spec
+spec = do
+  let gf = ("test_resources/csi/" ++)
+  describe "renderCSI" $ do
+    it "outputs a reset the same as before" $
+      pureGoldenByteStringFile (gf "reset.dat") (renderCSIBS (SGR [Reset]))
+    describe "SGR" $ do
+      let gf8 = ("test_resources/csi/8/" ++)
+      describe "8 colours" $ do
+        describe "simple, exhaustive" $ do
+          let sgrTests = do
+                intensity <- [minBound .. maxBound]
+                layer <- [minBound .. maxBound]
+                colour <- [minBound .. maxBound]
+                pure
+                  ( unwords [show intensity, show colour, show layer],
+                    map Char.toLower (intercalate "-" [show intensity, show colour, show layer]) ++ ".dat",
+                    SetColour intensity layer colour
+                  )
+          forM_ sgrTests $ \(name, path, sgr) ->
+            it (unwords ["outputs a", show name, "the same as before"]) $
+              pureGoldenByteStringFile (gf8 path) (renderCSIBS (SGR [sgr]))
+        it "outputs an dull red background with bright blue foreground the same as before" $ do
+          pureGoldenByteStringFile
+            (gf8 "two-colours.dat")
+            ( renderCSIBS
+                ( SGR
+                    [ SetColour Dull Background Red,
+                      SetColour Bright Foreground Blue
+                    ]
+                )
+            )
+        it "outputs an bold, italic, underlined, dull yellow background with bright green foreground the same as before" $ do
+          pureGoldenByteStringFile
+            (gf8 "complex.dat")
+            ( renderCSIBS
+                ( SGR
+                    [ SetItalic True,
+                      SetUnderlining SingleUnderline,
+                      SetConsoleIntensity BoldIntensity,
+                      SetColour Dull Background Yellow,
+                      SetColour Bright Foreground Green
+                    ]
+                )
+            )
+      let gf256 = ("test_resources/csi/256/" ++)
+      describe "256 colours" $ do
+        -- https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
+        it "outputs a pink foreground colour with light blue background the same as before" $ do
+          pureGoldenByteStringFile
+            (gf256 "two-colours.dat")
+            ( renderCSIBS
+                ( SGR
+                    [ SetColour Dull Background Red,
+                      SetColour Bright Foreground Blue
+                    ]
+                )
+            )
diff --git a/test/Text/ColourSpec.hs b/test/Text/ColourSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/Text/ColourSpec.hs
@@ -0,0 +1,22 @@
+{-# LANGUAGE TypeApplications #-}
+
+module Text.ColourSpec (spec) where
+
+import Test.Syd
+import Test.Syd.Validity
+import Text.Colour
+import Text.Colour.Code
+import Text.Colour.Gen ()
+
+spec :: Spec
+spec = do
+  genValidSpec @CSI
+  genValidSpec @ColourIntensity
+  genValidSpec @ConsoleIntensity
+  genValidSpec @ConsoleLayer
+  genValidSpec @SGR
+  genValidSpec @TerminalColour
+  genValidSpec @TerminalColour
+  genValidSpec @Underlining
+  genValidSpec @Colour
+  genValidSpec @Chunk