diff --git a/python/GafferSceneTest/ShaderTweaksTest.py b/python/GafferSceneTest/ShaderTweaksTest.py
index c369ab4da7a..3d519acaeb1 100644
--- a/python/GafferSceneTest/ShaderTweaksTest.py
+++ b/python/GafferSceneTest/ShaderTweaksTest.py
@@ -364,7 +364,7 @@ def testIgnoreMissing( self ) :
 		inputShader = GafferSceneTest.TestShader()
 		badTweak["value"].setInput( inputShader["out"]["r"] )
 
-		with self.assertRaisesRegex( RuntimeError, "Cannot apply tweak \"badParameter\" because shader \"light\" does not have parameter \"badParameter\"" ) :
+		with self.assertRaisesRegex( RuntimeError, "Cannot apply tweak \"badParameter\" because shader \"__shader\" does not have parameter \"badParameter\"" ) :
 			t["out"].attributes( "/light" )
 
 		badTweak["value"].setInput( None )