Add test cases for stylish-haskell

Author: Ailrun

test/functional/Format.hs

@@ -24,6 +24,7 @@ tests = testGroup "format document" [
         documentContents doc >>= liftIO . (`shouldBe` formattedDocTabSize5)
     , rangeTests
     , providerTests
+    , stylishHaskellTests
     , brittanyTests
     , ormoluTests
     ]
@@ -68,6 +69,16 @@ providerTests = testGroup "formatting provider" [
         documentContents doc >>= liftIO . (`shouldBe` formattedBrittanyPostFloskell)
     ]
 
+stylishHaskellTests :: TestTree
+stylishHaskellTests = testGroup "stylish-haskell" [
+  testCase "formats a file" $ runSession hieCommand fullCaps "test/testdata" $ do
+      sendNotification WorkspaceDidChangeConfiguration (DidChangeConfigurationParams (formatLspConfig "stylish-haskell"))
+      doc <- openDoc "StylishHaskell.hs" "haskell"
+      formatDoc doc (FormattingOptions 2 True)
+      contents <- documentContents doc
+      liftIO $ contents `shouldBe` formattedStylishHaskell
+  ]
+
 brittanyTests :: TestTree
 brittanyTests = testGroup "brittany" [
     ignoreTestBecause "Broken" $ testCase "formats a document with LF endings" $ runSession hieCommand fullCaps "test/testdata" $ do
@@ -175,6 +186,18 @@ formattedRangeTabSize5 =
   \\n\
   \data Baz = Baz { a :: Int, b :: String }\n\n"
 
+formattedStylishHaskell :: T.Text
+formattedStylishHaskell =
+  "import           Data.Char\n\
+  \import qualified Data.List\n\
+  \import           Data.String\n\
+  \\n\
+  \bar :: Maybe (Either String Integer) -> Integer\n\
+  \bar Nothing          = 0\n\
+  \bar (Just (Left _))  = 0\n\
+  \bar (Just (Right x)) = x\n\
+  \"
+
 formattedFloskell :: T.Text
 formattedFloskell =
   "module Format where\n\

test/testdata/StylishHaskell.hs

@@ -0,0 +1,8 @@
+import Data.Char
+import qualified Data.List
+import    Data.String
+
+bar :: Maybe (Either String Integer) -> Integer
+bar Nothing = 0
+bar (Just (Left _)) = 0
+bar (Just (Right x)) = x