test CmdRun/Terminate: add some debug logging

We've seen some instability in the test, compare

  https://github.com/haskell/cabal/issues/8416

This adds timestamped output to make it easier to
see what goes wrong in case the test fails again.

cabal-testsuite/PackageTests/NewBuild/CmdRun/Terminate/Main.hs

@@ -2,13 +2,21 @@ import Control.Concurrent (killThread, threadDelay, myThreadId)
 import Control.Exception (finally)
 import qualified System.Posix.Signals as Signal
 import System.Exit (exitFailure)
+import qualified Data.Time.Clock as Time
+import qualified Data.Time.Format as Time
 
 main = do
+  -- timestamped logging to aid with #8416
+  let log msg = do
+        ts <- Time.getCurrentTime
+        let tsfmt = Time.formatTime Time.defaultTimeLocale "%H:%M:%S.%q" ts
+        putStrLn $ tsfmt <> " [exe       ] " <> msg
   mainThreadId <- myThreadId
   Signal.installHandler Signal.sigTERM (Signal.Catch $ killThread mainThreadId) Nothing
   (do
-    putStrLn "about to sleep"
+    log "about to write file"
     writeFile "exe.run" "up and running"
+    log "about to sleep"
     threadDelay 10000000 -- 10s
-    putStrLn "done sleeping")
-    `finally` putStrLn "exiting"
+    log "done sleeping")
+    `finally` log "exiting"

cabal-testsuite/PackageTests/NewBuild/CmdRun/Terminate/RunKill.cabal

@@ -5,5 +5,5 @@ cabal-version: >= 1.10
 
 executable exe
   default-language: Haskell2010
-  build-depends: base, process, unix
+  build-depends: base, process, time, unix
   main-is: Main.hs

cabal-testsuite/PackageTests/NewBuild/CmdRun/Terminate/cabal.test.hs

@@ -4,6 +4,8 @@ import Control.Concurrent (threadDelay)
 import System.Directory (removeFile)
 import Control.Exception (catch, throwIO)
 import System.IO.Error (isDoesNotExistError)
+import qualified Data.Time.Clock as Time
+import qualified Data.Time.Format as Time
 
 {-
 This test verifies that 'cabal run' terminates its
@@ -18,16 +20,28 @@ main :: IO ()
 main = cabalTest $ do
   skipIfWindows -- test project relies on Posix
 
+  -- timestamped logging to aid with #8416
+  let logIO msg = do
+        ts <- Time.getCurrentTime
+        let tsfmt = Time.formatTime Time.defaultTimeLocale "%H:%M:%S.%q" ts
+        putStrLn $ tsfmt <> " [cabal.test] " <> msg
+      log = liftIO . logIO
+
   dir <- fmap testCurrentDir getTestEnv
   let runFile = dir </> "exe.run"
   liftIO $ removeFile runFile `catchNoExist` return ()
 
+  log "about to v2-build"
   cabal_raw_action ["v2-build", "exe"] (\_ -> return ())
+  log "about to v2-run"
   r <- fails $ cabal_raw_action ["v2-run", "exe"] $ \cabalHandle -> do
     -- wait for "cabal run" to have started "exe"
+    logIO "about to wait for file"
     waitFile total runFile
     -- then kill "cabal run"
+    logIO "about to terminate cabal"
     Process.terminateProcess cabalHandle
+  log "v2-run done"
 
   -- "exe" should exit, and should have been interrupted before
   -- finishing its sleep