Cleanup: move copy-paste code into function

tests/python/render_layer/test_evaluation_visibility_e.py

@@ -49,10 +49,6 @@ class UnitTesting(RenderLayerTesting):
 # ############################################################
 
 if __name__ == '__main__':
-    import sys
-
-    extra_arguments = sys.argv[sys.argv.index("--") + 2:] if "--" in sys.argv else []
-    sys.argv = [__file__] + (sys.argv[sys.argv.index("--") + 2:] if "--" in sys.argv else [])
-
-    UnitTesting._extra_arguments = extra_arguments
+    # XXX, above statement is not true, why skip the first argument?
+    UnitTesting._extra_arguments = setup_extra_arguments(__file__)[1:]
     unittest.main()