cabal-testsuite: Show instance for TestEnv

The `Show` instance for `TestEnv` is helpful in debugging testcases.
While it produces large Haskell expressions not for consumption by the
naked eye, it can be inspected in viewers like `ppshow`.

https://hackage.haskell.org/package/pretty-show

cabal-testsuite/src/Test/Cabal/Monad.hs

@@ -530,6 +530,7 @@ data TestEnv = TestEnv
     -- relative to 'testSourceDir'
     , testSourceCopyRelativeDir :: FilePath
     }
+    deriving Show
 
 testRecordMode :: TestEnv -> RecordMode
 testRecordMode env = fromMaybe (testRecordDefaultMode env) (testRecordUserMode env)

cabal-testsuite/src/Test/Cabal/Plan.hs

@@ -19,11 +19,13 @@ import Control.Monad
 
 -- TODO: index this
 data Plan = Plan { planInstallPlan :: [InstallItem] }
+  deriving Show
 
 data InstallItem
     = APreExisting
     | AConfiguredGlobal ConfiguredGlobal
     | AConfiguredInplace ConfiguredInplace
+  deriving Show
 
 -- local or inplace package
 data ConfiguredInplace = ConfiguredInplace
@@ -31,11 +33,13 @@ data ConfiguredInplace = ConfiguredInplace
     , configuredInplaceBuildInfo     :: Maybe FilePath
     , configuredInplacePackageName   :: PackageName
     , configuredInplaceComponentName :: Maybe ComponentName }
+  deriving Show
 
 data ConfiguredGlobal = ConfiguredGlobal
     { configuredGlobalBinFile       :: Maybe FilePath
     , configuredGlobalPackageName   :: PackageName
     , configuredGlobalComponentName :: Maybe ComponentName }
+  deriving Show
 
 instance FromJSON Plan where
     parseJSON (Object v) = fmap Plan (v .: "install-plan")

cabal-testsuite/src/Test/Cabal/Script.hs

@@ -37,6 +37,7 @@ data ScriptEnv = ScriptEnv
         , runnerPackages        :: [(OpenUnitId, ModuleRenaming)]
         , runnerWithSharedLib   :: Bool
         }
+    deriving Show
 
 {-