Add CustomTime time mode

src/Test/Tasty/Bench.hs

@@ -833,6 +833,8 @@ data TimeMode = CpuTime
   -- ^ Measure CPU time.
   | WallTime
   -- ^ Measure wall-clock time.
+  | CustomTime String (IO Word64)
+  -- ^ Custom measurement action.
 
 #ifdef MIN_VERSION_tasty
 instance IsOption RelStDev where
@@ -922,6 +924,7 @@ instance IsOption TimeMode where
   showDefaultValue m = Just $ case m of
     CpuTime -> "cpu"
     WallTime -> "wall"
+    CustomTime name _ -> name
 #endif
 
 -- | Something that can be benchmarked, produced by 'nf', 'whnf', 'nfIO', 'whnfIO',
@@ -1101,6 +1104,7 @@ getTimePicoSecs :: TimeMode -> IO Word64
 getTimePicoSecs timeMode = case timeMode of
   CpuTime -> fromInteger <$> getCPUTime
   WallTime -> round . (1e12 *) <$> getWallTimeSecs
+  CustomTime _ getCustomTime -> getCustomTime
 
 measure :: TimeMode -> Word64 -> Benchmarkable -> IO Measurement
 measure timeMode n (Benchmarkable act) = do