Starting to work on hedgehog documentation

sandwich-site/docs/extensions/sandwich-hedgehog.md

@@ -0,0 +1,48 @@
+---
+id: sandwich-hedgehog
+title: Hedgehog integration
+---
+
+You can use `sandwich-hedgehog` (provided as a separate package) to easily integrate integrate [Hedgehog](https://hedgehog.qa/) tests into the test tree.
+
+Haddocks can be found [here](http://hackage.haskell.org/package/sandwich-hedgehog/docs/Test-Sandwich-Hedgehog.html).
+
+## Usage
+
+To use `sandwich-hedgehog`, just add the package to your project. Then, introduce a Hedgehog argument context using [introduceHedgehog](http://hackage.haskell.org/package/sandwich-hedgehog/docs/Test-Sandwich-Hedgehog.html#v:introduceHedgehog). Now you can start writing props as test nodes using the [prop](http://hackage.haskell.org/package/sandwich-hedgehog/docs/Test-Sandwich-Hedgehog.html#v:prop) function. For example:
+
+```haskell title="https://github.com/codedownio/sandwich/blob/master/demos/demo-hedgehog/app/Main.hs"
+import Hedgehog
+import qualified Hedgehog.Gen as Gen
+import qualified Hedgehog.Range as Range
+
+hedgehogDemo :: TopSpec
+hedgehogDemo = describe "Hedgehog tests" $ introduceHedgehog $ do
+  prop "List reversal" $ do
+    xs <- forAll $ Gen.list (Range.linear 0 100) Gen.alpha
+    reverse (reverse xs) === xs
+
+  prop "Failing list reversal" $ do
+    xs <- forAll $ Gen.list (Range.linear 0 100) Gen.alpha
+    reverse xs === xs
+```
+
+## Demo
+
+A demo is provided in the Sandwich repo.
+
+```shell
+git clone git@github.com:codedownio/sandwich.git
+cd sandwich
+stack run demo-hedgehog -- --tui
+```
+
+<!-- ## Modifying the args -->
+
+<!-- If you use [introduceHedgehog'](http://hackage.haskell.org/package/sandwich-hedgehog/docs/Test-Sandwich-Hedgehog.html#v:introduceHedgehog'), you can pass your own value for the Hedgehog [Args](https://hackage.haskell.org/package/Hedgehog/docs/Test-Hedgehog.html#t:Args). The default version uses [stdArgs](https://hackage.haskell.org/package/Hedgehog/docs/Test-Hedgehog.html#v:stdArgs). -->
+
+<!-- If you want to modify the already-introduced arguments in a test tree, we provide the [modifyArgs](http://hackage.haskell.org/package/sandwich-hedgehog/docs/Test-Sandwich-Hedgehog.html#v:modifyArgs) function, as well as helpers like `modifyMaxSize`, `modifyMaxDiscardRatio`, etc. These are modelled directly after HSpec's [Test.Hspec.Hedgehog](https://hackage.haskell.org/package/hspec/docs/Test-Hspec-Hedgehog.html). -->
+
+<!-- ## Controlling Hedgehog parameters with command line args -->
+
+<!-- There are not (yet) any built-in command line arguments for controlling Hedgehog parameters such as `maxSize`. However, you can add [custom command line options](../command_line) to control any parameters you like. -->

sandwich-site/sidebars.js

@@ -14,10 +14,11 @@ module.exports = {
       "formatters/failure_report",
       "formatters/log_saver",
       "formatters/silent",
-      "formatters/slack"
+      "formatters/slack",
       "formatters/markdown_summary",
     ] },
     { type: "doc", id: "extensions/sandwich-webdriver" },
     { type: "doc", id: "extensions/sandwich-quickcheck" },
+    { type: "doc", id: "extensions/sandwich-hedgehog" },
   ],
 };