diff --git a/compiler/src/Reporting/Error/Syntax.hs b/compiler/src/Reporting/Error/Syntax.hs
index 894b006b..6cab29ce 100644
--- a/compiler/src/Reporting/Error/Syntax.hs
+++ b/compiler/src/Reporting/Error/Syntax.hs
@@ -70,6 +70,7 @@ data Error
   | NoPortModulesInPackage A.Region
   | NoEffectsOutsideKernel A.Region
   | ParseError Module
+  deriving (Show)
 
 -- MODULE
 
@@ -104,6 +105,7 @@ data Module
     Infix Row Col
   | --
     Declarations Decl Row Col
+  deriving (Show)
 
 data Exposing
   = ExposingSpace Space Row Col
@@ -117,6 +119,7 @@ data Exposing
   | --
     ExposingIndentEnd Row Col
   | ExposingIndentValue Row Col
+  deriving (Show)
 
 -- DECLARATIONS
 
@@ -129,6 +132,7 @@ data Decl
   | DeclDef Name.Name DeclDef Row Col
   | --
     DeclFreshLineAfterDocComment Row Col
+  deriving (Show)
 
 data DeclDef
   = DeclDefSpace Space Row Col
@@ -142,6 +146,7 @@ data DeclDef
     DeclDefIndentType Row Col
   | DeclDefIndentEquals Row Col
   | DeclDefIndentBody Row Col
+  deriving (Show)
 
 data Port
   = PortSpace Space Row Col
@@ -151,6 +156,7 @@ data Port
   | PortIndentName Row Col
   | PortIndentColon Row Col
   | PortIndentType Row Col
+  deriving (Show)
 
 -- TYPE DECLARATIONS
 
@@ -161,6 +167,7 @@ data DeclType
   | DT_Union CustomType Row Col
   | --
     DT_IndentName Row Col
+  deriving (Show)
 
 data TypeAlias
   = AliasSpace Space Row Col
@@ -170,6 +177,7 @@ data TypeAlias
   | --
     AliasIndentEquals Row Col
   | AliasIndentBody Row Col
+  deriving (Show)
 
 data CustomType
   = CT_Space Space Row Col
@@ -183,6 +191,7 @@ data CustomType
   | CT_IndentBar Row Col
   | CT_IndentAfterBar Row Col
   | CT_IndentAfterEquals Row Col
+  deriving (Show)
 
 -- EXPRESSIONS
 
diff --git a/gren.cabal b/gren.cabal
index e5e4b19c..30555217 100644
--- a/gren.cabal
+++ b/gren.cabal
@@ -249,8 +249,9 @@ Test-Suite gren-tests
         Helpers.Parse
 
         -- tests
-        Parse.SpaceSpec
+        Integration.FormatSpec
         Parse.RecordUpdateSpec
+        Parse.SpaceSpec
         Parse.UnderscorePatternSpec
 
     Build-Depends:
diff --git a/terminal/src/Format.hs b/terminal/src/Format.hs
index 47b9fd6d..4cc0c9c9 100644
--- a/terminal/src/Format.hs
+++ b/terminal/src/Format.hs
@@ -3,6 +3,7 @@
 module Format
   ( Flags (..),
     run,
+    formatByteString,
   )
 where
 
diff --git a/tests/Integration/FormatSpec.hs b/tests/Integration/FormatSpec.hs
new file mode 100644
index 00000000..12136d1d
--- /dev/null
+++ b/tests/Integration/FormatSpec.hs
@@ -0,0 +1,62 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+-- | Integration tests for formatting that cover both the parsing and formatting
+-- (tests go from text to text).
+module Integration.FormatSpec where
+
+import Data.ByteString.Builder qualified as Builder
+import Data.Text (Text)
+import Data.Text qualified as Text
+import Data.Text.Encoding qualified as TE
+import Data.Text.Lazy qualified as LazyText
+import Data.Text.Lazy.Encoding qualified as LTE
+import Format qualified
+import Test.Hspec
+
+spec :: Spec
+spec = do
+  describe "top-level definition" $ do
+    it "formats" $
+      ["f = {}"]
+        `shouldFormatModuleBodyAs` [ "f =",
+                                     "    {}"
+                                   ]
+  describe "expressions" $ do
+    describe "record" $ do
+      it "formats with fields" $
+        ["{a=1,   b = 2}"]
+          `shouldFormatExpressionAs` [ "{ a = 1",
+                                       ", b = 2",
+                                       "}"
+                                     ]
+
+shouldFormatModuleBodyAs :: [Text] -> [LazyText.Text] -> IO ()
+shouldFormatModuleBodyAs inputLines expectedOutputLines =
+  let input = TE.encodeUtf8 $ Text.unlines inputLines
+      expectedOutput = LazyText.unlines expectedOutputLines
+      actualOutput = LTE.decodeUtf8 . Builder.toLazyByteString <$> Format.formatByteString input
+   in case LazyText.stripPrefix "module Main exposing (..)\n\n\n\n" <$> actualOutput of
+        Nothing ->
+          expectationFailure "shouldFormatModuleBodyAs: failed to format"
+        Just Nothing ->
+          expectationFailure "shouldFormatModuleBodyAs: internal error: could not strip module header"
+        Just (Just actualModuleBody) ->
+          actualModuleBody `shouldBe` expectedOutput
+
+shouldFormatExpressionAs :: [Text] -> [LazyText.Text] -> IO ()
+shouldFormatExpressionAs inputLines expectedOutputLines =
+  let input = TE.encodeUtf8 $ "expr = " <> Text.unlines inputLines
+      expectedOutput = LazyText.unlines expectedOutputLines
+      actualOutput = LTE.decodeUtf8 . Builder.toLazyByteString <$> Format.formatByteString input
+      cleanOutput i =
+        LazyText.stripPrefix "module Main exposing (..)\n\n\n\nexpr =\n" i
+          >>= (return . LazyText.lines)
+          >>= traverse (LazyText.stripPrefix "    ")
+          >>= (return . LazyText.unlines)
+   in case fmap cleanOutput actualOutput of
+        Nothing ->
+          expectationFailure "shouldFormatExpressionAs: failed to format"
+        Just Nothing ->
+          expectationFailure "shouldFormatExpressionAs: internal error: could clean output"
+        Just (Just actualExpression) ->
+          actualExpression `shouldBe` expectedOutput