Use LineBuffering in unit tests

lib/core-integration/src/Cardano/Wallet/BenchShared.hs

@@ -99,8 +99,8 @@ import System.Exit
     ( ExitCode (..), die )
 import System.FilePath
     ( (</>) )
-import System.IO
-    ( BufferMode (..), hSetBuffering, stderr, stdout )
+import Test.Utils.Startup
+    ( withNoBuffering )
 import UnliftIO.Concurrent
     ( threadDelay )
 import UnliftIO.Exception
@@ -121,12 +121,9 @@ execBenchWithNode
     -> (Trace IO Text -> cfg -> CardanoNodeConn -> IO ())
     -- ^ Action to run
     -> IO ExitCode
-execBenchWithNode networkConfig action = do
+execBenchWithNode networkConfig action = withNoBuffering $ do
     args <- getRestoreBenchArgs
 
-    hSetBuffering stdout NoBuffering
-    hSetBuffering stderr NoBuffering
-
     (_logCfg, tr') <- initBenchmarkLogging "bench-restore" Info
     let tr = if argQuiet args then nullTracer else tr'
     installSignalHandlers (return ())

lib/core/test/unit/Cardano/Wallet/Api/Server/TlsSpec.hs

@@ -78,7 +78,7 @@ import Test.Hspec
     ( Spec, describe, it, shouldBe, shouldThrow )
 import Test.Utils.Paths
     ( getTestData )
-import Test.Utils.Windows
+import Test.Utils.Platform
     ( pendingOnWine )
 import UnliftIO.Async
     ( async, link )

lib/core/test/unit/Cardano/Wallet/Api/ServerSpec.hs

@@ -81,7 +81,7 @@ import Test.QuickCheck.Monadic
     ( PropertyM, assert, monadicIO, monitor, run )
 import Test.QuickCheck.Property
     ( counterexample, property )
-import Test.Utils.Windows
+import Test.Utils.Platform
     ( skipOnWindows )
 import UnliftIO.Async
     ( concurrently_, race_ )

lib/core/test/unit/Cardano/Wallet/DB/MVarSpec.hs

@@ -35,7 +35,7 @@ import Test.Hspec
     ( Spec, before, describe )
 import Test.QuickCheck
     ( Arbitrary (..) )
-import Test.Utils.Darwin
+import Test.Utils.Platform
     ( pendingOnMacOS )
 
 import qualified Cardano.Wallet.DB.MVar as MVar

lib/core/test/unit/Main.hs

@@ -1,10 +1,15 @@
 module Main where
 
+import Prelude
+
 import Cardano.Startup
     ( withUtf8Encoding )
-import Prelude
-import qualified Spec
 import Test.Hspec.Runner
+    ( defaultConfig, hspecWith )
+import Test.Utils.Startup
+    ( withLineBuffering )
+
+import qualified Spec
 
 main :: IO ()
-main = withUtf8Encoding $ hspecWith defaultConfig Spec.spec
+main = withLineBuffering $ withUtf8Encoding $ hspecWith defaultConfig Spec.spec

lib/core/test/unit/Network/Wai/Middleware/LoggingSpec.hs

@@ -96,7 +96,7 @@ import Test.QuickCheck
     ( Arbitrary (..), choose, counterexample, property, withMaxSuccess )
 import Test.QuickCheck.Monadic
     ( assert, monadicIO, monitor )
-import Test.Utils.Darwin
+import Test.Utils.Platform
     ( pendingOnMacOS )
 import UnliftIO.Async
     ( Async, async, cancel, mapConcurrently, replicateConcurrently_ )

lib/launcher/test/unit/Cardano/LauncherSpec.hs

@@ -61,7 +61,7 @@ import Test.Hspec
     , shouldReturn
     , shouldSatisfy
     )
-import Test.Utils.Windows
+import Test.Utils.Platform
     ( isWindows, pendingOnWine, skipOnWindows )
 import UnliftIO.Async
     ( async, race_, waitAnyCancel )

lib/launcher/test/unit/Cardano/StartupSpec.hs

@@ -29,10 +29,10 @@ import Test.Hspec.Core.Spec
     ( ResultStatus (..) )
 import Test.Hspec.Expectations
     ( Expectation, HasCallStack )
+import Test.Utils.Platform
+    ( nullFileName, pendingOnWindows )
 import Test.Utils.Trace
     ( captureLogging )
-import Test.Utils.Windows
-    ( nullFileName, pendingOnWindows )
 import UnliftIO.Async
     ( race )
 import UnliftIO.Concurrent

lib/shelley/test/integration/Main.hs

@@ -115,8 +115,6 @@ import System.Environment
     ( setEnv )
 import System.FilePath
     ( (</>) )
-import System.IO
-    ( BufferMode (..), hSetBuffering, stderr, stdout )
 import Test.Hspec
     ( hspec )
 import Test.Hspec.Core.Spec
@@ -134,6 +132,8 @@ import Test.Integration.Framework.Context
     ( Context (..), PoolGarbageCollectionEvent (..) )
 import Test.Utils.Paths
     ( getTestData, inNixBuild )
+import Test.Utils.Startup
+    ( withLineBuffering )
 import UnliftIO.Async
     ( race )
 import UnliftIO.Exception
@@ -223,16 +223,14 @@ withTestsSetup :: (FilePath -> (Tracer IO TestsLog, Tracers IO) -> IO a) -> IO a
 withTestsSetup action = do
     -- Handle SIGTERM properly
     installSignalHandlersNoLogging
-    -- Flush test output as soon as a line is printed
-    hSetBuffering stdout LineBuffering
-    hSetBuffering stderr LineBuffering
     -- Stop cardano-cli complaining about file permissions
     setDefaultFilePermissions
     -- Enables small test-specific workarounds, like timing out faster if wallet
     -- deletion fails.
     setEnv "CARDANO_WALLET_TEST_INTEGRATION" "1"
-    -- Set UTF-8, regardless of user locale
-    withUtf8Encoding $
+    -- Flush test output as soon as a line is printed.
+    -- Set UTF-8, regardless of user locale.
+    withLineBuffering $ withUtf8Encoding $
         -- This temporary directory will contain logs, and all other data
         -- produced by the integration tests.
         withSystemTempDir stdoutTextTracer "test" $ \testDir ->

lib/shelley/test/unit/Cardano/Wallet/Shelley/LaunchSpec.hs

@@ -13,7 +13,7 @@ import Options.Applicative
     ( ParserResult (..), defaultPrefs, execParserPure, info )
 import Test.Hspec
     ( Spec, describe, it, shouldSatisfy )
-import Test.Utils.Windows
+import Test.Utils.Platform
     ( isWindows )
 
 spec :: Spec

lib/test-utils/cardano-wallet-test-utils.cabal

@@ -57,17 +57,17 @@ library
   exposed-modules:
       Test.Hspec.Extra
       Test.QuickCheck.Extra
-      Test.Utils.Darwin
       Test.Utils.FilePath
       Test.Utils.Laws
       Test.Utils.Laws.PartialOrd
       Test.Utils.Paths
       Test.Utils.Roundtrip
       Test.Utils.Resource
+      Test.Utils.Platform
+      Test.Utils.Startup
       Test.Utils.StaticServer
       Test.Utils.Time
       Test.Utils.Trace
-      Test.Utils.Windows
 
 test-suite unit
   default-language:

lib/test-utils/src/Test/Hspec/Extra.hs

@@ -39,10 +39,10 @@ import Test.Hspec
     )
 import Test.HUnit.Lang
     ( HUnitFailure (..), assertFailure, formatFailureReason )
+import Test.Utils.Platform
+    ( isWindows )
 import Test.Utils.Resource
     ( unBracket )
-import Test.Utils.Windows
-    ( isWindows )
 import UnliftIO.Async
     ( race )
 import UnliftIO.Concurrent

lib/test-utils/src/Test/Utils/Darwin.hs

@@ -1,27 +0,0 @@
--- |
--- Copyright: © 2018-2021 IOHK
--- License: Apache-2.0
---
--- Utility function for making test suites pass on Darwin/macOS.
-
-module Test.Utils.Darwin
-    ( pendingOnMacOS
-    ) where
-
-import Prelude
-
-import Control.Monad
-    ( when )
-import System.Info
-    ( os )
-import Test.Hspec.Core.Spec
-    ( pendingWith )
-import Test.Hspec.Expectations
-    ( Expectation, HasCallStack )
-
--- | Mark test pending if running on macOS
-pendingOnMacOS :: HasCallStack => String -> Expectation
-pendingOnMacOS reason = when isDarwin $ pendingWith reason
-
-isDarwin :: Bool
-isDarwin = os == "darwin"

lib/test-utils/src/Test/Utils/FilePath.hs

@@ -14,7 +14,7 @@ import System.FilePath.Windows
     ( makeValid )
 import Test.QuickCheck
     ( Arbitrary (..), elements, listOf1, scale )
-import Test.Utils.Windows
+import Test.Utils.Platform
     ( isWindows )
 
 -- | A file or directory name. The 'Arbitrary' instance will generate values

lib/test-utils/src/Test/Utils/Windows.hs → lib/test-utils/src/Test/Utils/Platform.hs

@@ -2,19 +2,26 @@
 {-# LANGUAGE ScopedTypeVariables #-}
 
 -- |
--- Copyright: © 2018-2020 IOHK
+-- Copyright: © 2018-2021 IOHK
 -- License: Apache-2.0
 --
--- Utility function for making test suites pass on Windows.
+-- Utility function for making test suites pass on difficult platforms.
 
-module Test.Utils.Windows
-    ( skipOnWindows
+module Test.Utils.Platform
+    ( -- * Skipping tests
+      skipOnWindows
     , pendingOnWindows
     , pendingOnWine
+    , pendingOnMacOS
+
+    -- * OS detection
     , whenWindows
     , isWindows
-    , nullFileName
+    , isMacOS
     , getIsWine
+
+    -- * Cross-platform compatibility
+    , nullFileName
     ) where
 
 import Prelude
@@ -45,11 +52,16 @@ pendingOnWine reason = whenWindows $ do
     wine <- getIsWine
     when wine $ pendingWith reason
 
-whenWindows :: IO () -> IO ()
-whenWindows = when isWindows
+-- | Mark test pending if running on macOS
+pendingOnMacOS :: HasCallStack => String -> Expectation
+pendingOnMacOS reason = when isMacOS $ pendingWith reason
 
-isWindows :: Bool
+isWindows, isMacOS :: Bool
 isWindows = os == "mingw32"
+isMacOS = os == "darwin"
+
+whenWindows :: IO () -> IO ()
+whenWindows = when isWindows
 
 -- | Use the presence of @winepath.exe@ to detect when running tests under Wine.
 getIsWine :: IO Bool

lib/test-utils/src/Test/Utils/Startup.hs

@@ -0,0 +1,39 @@
+module Test.Utils.Startup
+    ( withLineBuffering
+    , withNoBuffering
+    ) where
+
+import Prelude
+
+import Control.Monad
+    ( void )
+import Control.Monad.IO.Unlift
+    ( MonadUnliftIO )
+import UnliftIO.Exception
+    ( IOException, bracket, tryJust )
+import UnliftIO.IO
+    ( BufferMode (..), hGetBuffering, hSetBuffering, stderr, stdout )
+
+withLineBuffering, withNoBuffering :: MonadUnliftIO m => m a -> m a
+withLineBuffering = withBuffering LineBuffering
+withNoBuffering = withBuffering NoBuffering
+
+withBuffering :: MonadUnliftIO m => BufferMode -> m a -> m a
+withBuffering mode = bracket before after . const
+  where
+    before = do
+        prev <- (,) <$> getBuf stdout <*> getBuf stderr
+        setBuf stdout (Just mode)
+        setBuf stderr (Just mode)
+        pure prev
+    after (prevOut, prevErr) = do
+        setBuf stdout prevOut
+        setBuf stderr prevErr
+
+    getBuf = tryErr . hGetBuffering
+    setBuf h = maybe (pure ()) (void . tryErr . hSetBuffering h)
+
+    -- Swallow any IO errors
+    tryErr = fmap (either (const Nothing) Just) . tryJust isAlright
+    isAlright :: IOException -> Maybe ()
+    isAlright = const (Just ())