Per-field GenericPackageDescription golden test

Cabal-tests/tests/ParserTests.hs

@@ -14,7 +14,19 @@ import Control.Monad                               (unless, void)
 import Data.Algorithm.Diff                         (PolyDiff (..), getGroupedDiff)
 import Data.Maybe                                  (isNothing)
 import Distribution.Fields                         (pwarning)
-import Distribution.PackageDescription             (GenericPackageDescription)
+import Distribution.PackageDescription
+  ( GenericPackageDescription
+      ( packageDescription
+      , gpdScannedVersion
+      , genPackageFlags
+      , condLibrary
+      , condSubLibraries
+      , condForeignLibs
+      , condExecutables
+      , condTestSuites
+      , condBenchmarks
+    )
+  )
 import Distribution.PackageDescription.Parsec      (parseGenericPackageDescription)
 import Distribution.PackageDescription.PrettyPrint (showGenericPackageDescription)
 import Distribution.Parsec                         (PWarnType (..), PWarning (..), showPErrorWithSource, showPWarningWithSource)
@@ -237,7 +249,16 @@ treeDiffGoldenTest fp = ediffGolden goldenTest "expr" exprFile $ do
     let res = withSource (PCabalFile (fp, contents)) $ parseGenericPackageDescription contents
     let (_, x) = runParseResult res
     case x of
-        Right gpd      -> pure (toExpr gpd)
+        Right gpd      -> pure $ toExpr
+          ( gpd
+          -- Test accessors because they encapsulate the merging behaviour
+          , condLibrary gpd
+          , condSubLibraries gpd
+          , condForeignLibs gpd
+          , condExecutables gpd
+          , condTestSuites gpd
+          , condBenchmarks gpd
+          )
         Left (_, errs) -> fail $ unlines $ "ERROR" : map (showPErrorWithSource . fmap renderCabalFileSource) (NE.toList errs)
   where
     input = "tests" </> "ParserTests" </> "regressions" </> fp
@@ -250,24 +271,38 @@ formatRoundTripTest fp = testCase "roundtrip" $ do
     x <- parse contents
     let contents' = showGenericPackageDescription x
     y <- parse (toUTF8BS contents')
-    -- previously we mangled licenses a bit
-    let y' = y
+
+    let checkField field =
+          unless (field x == field y) $
 {- FOURMOLU_DISABLE -}
-    unless (x == y') $
 #ifdef MIN_VERSION_tree_diff
-        assertFailure $ unlines
-            [ "re-parsed doesn't match"
-            , show $ ansiWlEditExpr $ ediff x y
-            ]
+            assertFailure $ unlines
+                [ "re-parsed doesn't match"
+                , show $ ansiWlEditExpr $ ediff x y
+                ]
 #else
-        assertFailure $ unlines
-            [ "re-parsed doesn't match"
-            , "expected"
-            , show x
-            , "actual"
-            , show y
-            ]
+            assertFailure $ unlines
+                [ "re-parsed doesn't match"
+                , "expected"
+                , show x
+                , "actual"
+                , show y
+                ]
 #endif
+    -- Due to the imports being merged, the structural comparison will fail
+    -- Instead, we check the equality after merging
+    sequence_
+      [ checkField packageDescription
+      , checkField gpdScannedVersion
+      , checkField genPackageFlags
+      , checkField condLibrary
+      , checkField condSubLibraries
+      , checkField condForeignLibs
+      , checkField condExecutables
+      , checkField condTestSuites
+      , checkField condBenchmarks
+      ]
+
   where
     parse :: BS.ByteString -> IO GenericPackageDescription
     parse c = do