diff --git a/tests/regression/issue_494/SConscript b/tests/regression/issue_494/SConscript
index 3ad59a3..07709ea 100644
--- a/tests/regression/issue_494/SConscript
+++ b/tests/regression/issue_494/SConscript
@@ -9,8 +9,10 @@
 # define which had the problem with C++.
 
 generator_cmd = os.path.join(env['NANOPB'], 'generator-bin', 'nanopb_generator' + env['PROGSUFFIX'])
-if not os.path.exists(generator_cmd):
-    generator_cmd = sys.executable + " " + os.path.join(env['NANOPB'], 'generator', 'nanopb_generator.py')
+if os.path.exists(generator_cmd):
+    generator_cmd = env['ESCAPE'](generator_cmd)
+else:
+    generator_cmd = env['ESCAPE'](sys.executable) + " " + env['ESCAPE'](os.path.join(env['NANOPB'], 'generator', 'nanopb_generator.py'))
 
 env.Command("oneof.pb", "oneof.proto", "$PROTOC $PROTOCFLAGS -Ibuild/regression/issue_494 -o$TARGETS $SOURCES")
 env.Command(["oneof.pb.c", "oneof.pb.h"], "oneof.pb", generator_cmd + " -Dbuild/regression/issue_494 $SOURCES")