IECoreScene tests : Tighten up a couple test timings

contrib/IECoreAlembic/test/IECoreAlembic/AlembicSceneTest.py

@@ -1929,7 +1929,7 @@ def backgroundRun():
 		startTime = time.time()
 		thread.start()
 
-		time.sleep( 0.05 )
+		time.sleep( 0.01 )
 		canceller.cancel()
 		thread.join()
 

src/IECoreScene/MeshAlgoTriangulate.cpp

@@ -315,6 +315,9 @@ MeshPrimitivePtr MeshAlgo::triangulate(
 		throw InvalidArgumentException( "MeshAlgo::triangulate : Mesh with invalid primitive variables" );
 	}
 
+	// arePrimitiveVariablesValid is expensive enough that we should check the canceller after running it.
+	Canceller::check( canceller );
+
 	// already triangulated
 	if ( mesh->maxVerticesPerFace() == 3 )
 	{

test/IECoreScene/MeshAlgoTriangulateTest.py

@@ -295,13 +295,13 @@ def backgroundRun():
 		startTime = time.time()
 		thread.start()
 
-		time.sleep( 0.1 )
+		time.sleep( 0.01 )
 		canceller.cancel()
 		thread.join()
 
 		# This test should actually produce a time extremely close to the sleep duration ( within
 		# 0.01 seconds whether the sleep duration is 0.01 seconds or 1 seconds ), but checking
-		# that it terminates with 0.1 seconds is a minimal performance bar
+		# that it terminates with 0.2 seconds is a minimal performance bar
 		self.assertLess( time.time() - startTime, 0.2 )
 		self.assertTrue( cancelled[0] )
 

test/IECoreScene/PrimitiveTest.py

@@ -202,7 +202,7 @@ def backgroundRun():
 		startTime = time.time()
 		thread.start()
 
-		time.sleep( 0.05 )
+		time.sleep( 0.01 )
 		canceller.cancel()
 		thread.join()