diff --git a/lib/roken/parse_time-test.c b/lib/roken/parse_time-test.c
index e2fcf3ac1..5f6170766 100644
--- a/lib/roken/parse_time-test.c
+++ b/lib/roken/parse_time-test.c
@@ -54,31 +54,32 @@ int
 main(int argc, char **argv)
 {
     size_t sz;
+    size_t buf_sz;
     int i, j;
 
     for (i = 0; i < sizeof(tests)/sizeof(tests[0]); ++i) {
 	char *buf;
 
-	for (j = 1; j < tests[i].size + 2; j++) {
+	for (buf_sz = 0; buf_sz < tests[i].size + 2; buf_sz++) {
 
 	    buf = rk_test_mem_alloc(RK_TM_OVERRUN, "overrun",
-				    NULL, j);
-	    sz = unparse_time(tests[i].val, buf, j);
+				    NULL, buf_sz);
+	    sz = unparse_time(tests[i].val, buf, buf_sz);
 	    if (sz != tests[i].size)
 		errx(1, "sz (%lu) != tests[%d].size (%lu)",
-		     (unsigned long)sz, i, 
+		     (unsigned long)buf_sz, i, 
 		     (unsigned long)tests[i].size);
-	    if (strncmp(buf, tests[i].str, j - 1) != 0)
+	    if (buf_sz > 0 && memcmp(buf, tests[i].str, buf_sz - 1) != 0)
 		errx(1, "test %i wrong result %s vs %s", i, buf, tests[i].str);
 	    rk_test_mem_free("overrun");
 
 	    buf = rk_test_mem_alloc(RK_TM_UNDERRUN, "underrun", 
 				    NULL, tests[i].size);
-	    sz = unparse_time(tests[i].val, buf, j);
+	    sz = unparse_time(tests[i].val, buf, buf_sz);
 	    if (sz != tests[i].size)
 		errx(1, "sz (%lu) != tests[%d].size (%lu)",
 		     (unsigned long)sz, i, (unsigned long)tests[i].size);
-	    if (strncmp(buf, tests[i].str, j - 1) != 0)
+	    if (buf_sz > 0 && strncmp(buf, tests[i].str, buf_sz - 1) != 0)
 		errx(1, "test %i wrong result %s vs %s", i, buf, tests[i].str);
 	    rk_test_mem_free("underrun");
 	}