Disable T-signals-child test on single-threaded runtime

As identified by Joachim, this test broke the Travis build. It appears
that this is due to the usage of the single-threaded runtime there. I've
confirmed that this fix causes the Travis build to pass:
https://travis-ci.org/snoyberg/ghc/builds/167368988.

Test Plan: Confirm tests now pass

Reviewers: austin, nomeata, bgamari

Reviewed By: nomeata, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2593

2 files changed, 10 insertions, 3 deletions

diff --git a/testsuite/tests/runghc/T-signals-child.hs b/testsuite/tests/runghc/T-signals-child.hs
index 21c1b646ae..ee36f62121 100644
--- a/testsuite/tests/runghc/T-signals-child.hs
+++ b/testsuite/tests/runghc/T-signals-child.hs
@@ -1,7 +1,7 @@
 import Control.Concurrent.MVar  (readMVar)
 import System.Environment       (getArgs)
 import System.Exit              (ExitCode (ExitFailure), exitFailure)
-import System.IO                (hGetLine, hPutStrLn)
+import System.IO                (hClose, hGetLine, hPutStrLn)
 import System.Posix.Process     (exitImmediately, getProcessID)
 import System.Posix.Signals     (Handler (Catch), installHandler, sigHUP,
                                  signalProcess)
@@ -9,6 +9,7 @@ import System.Process           (StdStream (CreatePipe), createProcess, proc,
                                  std_in, std_out, waitForProcess)
 import System.Process.Internals (ProcessHandle (..),
                                  ProcessHandle__ (OpenHandle))
+import System.Timeout           (timeout)
 
 main :: IO ()
 main = do
@@ -46,6 +47,7 @@ runParent runghc = do
     -- Send the child some input so that it will exit if it didn't
     -- have a sigHUP handler installed.
     hPutStrLn inH ""
+    hClose inH
 
     -- Read out the rest of stdout from the child, which will be
     -- either "NOSIGNAL\n" or "HUP\n"
@@ -95,7 +97,10 @@ runChild = do
     -- Block until we receive input, giving a chance for the signal
     -- handler to be triggered, and if the signal handler isn't
     -- triggered, gives us an escape route from this function.
-    _ <- getLine
+    --
+    -- Include a reasonable timeout to prevent this from running for
+    -- too long
+    _ <- timeout 10000000 getLine
 
     -- Reaching this point indicates a failure of the test. Print some
     -- non HUP message and exit with a non HUP exit
diff --git a/testsuite/tests/runghc/all.T b/testsuite/tests/runghc/all.T
index 107f35b74b..01337bca42 100644
--- a/testsuite/tests/runghc/all.T
+++ b/testsuite/tests/runghc/all.T
@@ -10,6 +10,8 @@ test('T11247', [req_interp, expect_broken(11247)], run_command,
 test('T6132', [when(opsys('darwin'), expect_broken(6132))], compile, [''])
 
 test('T-signals-child',
-     [when(opsys('mingw32'), skip), req_interp],
+     [ when(opsys('mingw32'), skip), req_interp
+     , only_ways(['threaded1', 'threaded2'])
+     ],
      run_command,
      ['$MAKE --no-print-directory -s T-signals-child'])