diff --git a/extra/c/preprocessor/preprocessor-tests.factor b/extra/c/preprocessor/preprocessor-tests.factor
index ba0531dfe7..7b0dedea46 100644
--- a/extra/c/preprocessor/preprocessor-tests.factor
+++ b/extra/c/preprocessor/preprocessor-tests.factor
@@ -1,6 +1,7 @@
 ! Copyright (C) 2009 Doug Coleman.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: tools.test c.preprocessor kernel accessors multiline ;
+USING: tools.test c.preprocessor kernel accessors multiline
+nested-comments ;
 IN: c.preprocessor.tests
 
 [ "vocab:c/tests/test1/test1.c" start-preprocess-file ]
@@ -9,18 +10,18 @@ IN: c.preprocessor.tests
 [ "yo\n\n\n\nyo4\n" ]
 [ "vocab:c/tests/test2/test2.c" start-preprocess-file nip ] unit-test
 
-/*
+(*
 [ "vocab:c/tests/test3/test3.c" start-preprocess-file ]
 [ "\"BOO\"" = ] must-fail-with
-*/
+*)
 
 [ V{ "\"omg\"" "\"lol\"" } ]
 [ "vocab:c/tests/test4/test4.c" start-preprocess-file drop warnings>> ] unit-test
 
 
-/*
+(*
 f(2 * (y+1)) + f(2 * (f(2 * (z[0])))) % f(2 * (0)) + t(1); 
 f(2 * (2+(3,4)-0,1)) | f(2 * (~ 5)) & f(2 * (0,1))^m(0,1); 
 int i[] = { 1, 23, 4, 5, }; 
 char c[2][6] = { "hello", "" }; 
-*/
+*)