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authorTom Sydney Kerckhove <syd@fpcomplete.com>2017-10-18 16:27:56 -0400
committerBen Gamari <ben@smart-cactus.org>2017-10-19 16:40:09 -0400
commit13758c6cfec1cfc8211d8c549ab69ee269f15b1e (patch)
tree30710631aae61ac115e4aac6f54d1f5f869feb7b
parent1ba28510e0731d91fcab560269c4ed5950d5e458 (diff)
downloadhaskell-13758c6cfec1cfc8211d8c549ab69ee269f15b1e.tar.gz
Added a test for 'timeout' to be accurate.
This is the first in a series of regression tests prompted by https://ghc.haskell.org/trac/ghc/ticket/8684 and D4011, D4012, D4041 Test Plan: This _is_ a test. Reviewers: nh2, austin, hvr, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie GHC Trac Issues: #8684 Differential Revision: https://phabricator.haskell.org/D4074
-rw-r--r--libraries/base/tests/all.T1
-rw-r--r--libraries/base/tests/timeout-accurate-pure.hs28
-rw-r--r--libraries/base/tests/timeout-accurate-pure.stdout2
3 files changed, 31 insertions, 0 deletions
diff --git a/libraries/base/tests/all.T b/libraries/base/tests/all.T
index 9055bd5b45..a1eba6a465 100644
--- a/libraries/base/tests/all.T
+++ b/libraries/base/tests/all.T
@@ -190,6 +190,7 @@ test('T8089',
[exit_code(99), run_timeout_multiplier(0.01)],
compile_and_run, [''])
test('T8684', expect_broken(8684), compile_and_run, [''])
+test('timeout-accurate-pure', normal, compile_and_run, [''])
test('T9826',normal, compile_and_run,[''])
test('T9848',
[ stats_num_field('bytes allocated',
diff --git a/libraries/base/tests/timeout-accurate-pure.hs b/libraries/base/tests/timeout-accurate-pure.hs
new file mode 100644
index 0000000000..a59e785a01
--- /dev/null
+++ b/libraries/base/tests/timeout-accurate-pure.hs
@@ -0,0 +1,28 @@
+import Control.Concurrent
+import Control.Monad
+import GHC.Clock
+import System.IO
+import System.Timeout
+
+ack :: Integer -> Integer -> Integer
+ack 0 n = n + 1
+ack m 0 = ack (m - 1) 1
+ack m n = ack (m - 1) (ack m (n - 1))
+
+main :: IO ()
+main = do
+ let microsecondsPerSecond = 1000 * 1000
+ let timeToSpend = 1 * microsecondsPerSecond -- One second in microseconds
+ start <- getMonotonicTimeNSec
+ timeout timeToSpend $
+ -- Something that is guaranteed not to be done in 'timeToSpend'
+ print $ ack 4 2
+ end <- getMonotonicTimeNSec
+ let timeSpentNano = fromIntegral $ end - start -- in nanoseconds
+ let nanosecondsPerMicrosecond = 1000
+ let timeToSpendNano = timeToSpend * nanosecondsPerMicrosecond
+ let legRoom = 1 * 1000 * nanosecondsPerMicrosecond -- Nanoseconds
+ let delta = timeSpentNano - timeToSpendNano
+ -- We can never wait for a shorter amount of time than specified
+ putStrLn $ "delta > 0: " ++ show (delta > 0)
+ putStrLn $ "delta < legroom: " ++ show (delta < legRoom)
diff --git a/libraries/base/tests/timeout-accurate-pure.stdout b/libraries/base/tests/timeout-accurate-pure.stdout
new file mode 100644
index 0000000000..90f4a4c7e8
--- /dev/null
+++ b/libraries/base/tests/timeout-accurate-pure.stdout
@@ -0,0 +1,2 @@
+delta > 0: True
+delta < legroom: True