diff --git a/python/IECoreRenderManTest/RendererTest.py b/python/IECoreRenderManTest/RendererTest.py
index a6e593b987..7025465cf1 100644
--- a/python/IECoreRenderManTest/RendererTest.py
+++ b/python/IECoreRenderManTest/RendererTest.py
@@ -121,12 +121,16 @@ def testOutput( self ) :
 		del r
 
 		self.assertTrue( ( self.temporaryDirectory() / "rgb.exr" ).is_file() )
-		imageSpec = OpenImageIO.ImageInput.open( str( self.temporaryDirectory() / "rgb.exr" ) ).spec()
+		imageFile = OpenImageIO.ImageInput.open( str( self.temporaryDirectory() / "rgb.exr" ) )
+		imageSpec = imageFile.spec()
+		imageFile.close()
 		self.assertEqual( imageSpec.nchannels, 3 )
 		self.assertEqual( imageSpec.channelnames, ( "R", "G", "B" ) )
 
 		self.assertTrue( ( self.temporaryDirectory() / "rgba.exr" ).is_file() )
-		imageSpec = OpenImageIO.ImageInput.open( str( self.temporaryDirectory() / "rgba.exr" ) ).spec()
+		imageFile = OpenImageIO.ImageInput.open( str( self.temporaryDirectory() / "rgba.exr" ) )
+		imageSpec = imageFile.spec()
+		imageFile.close()
 		self.assertEqual( imageSpec.nchannels, 4 )
 		self.assertEqual( imageSpec.channelnames, ( "R", "G", "B", "A" ) )