diff --git a/src/benchmark.c b/src/benchmark.c
index 918f87c..5c92706 100644
--- a/src/benchmark.c
+++ b/src/benchmark.c
@@ -58,8 +58,8 @@ HBenchmarkResults *h_benchmark__m(HAllocator* mm__, HParser* parser, HParserTest
 	res_unamb = h_write_result_unamb(res->ast);
       } else
 	res_unamb = NULL;
-      if ((res_unamb == NULL && tc->output_unambiguous == NULL)
-	  || (strcmp(res_unamb, tc->output_unambiguous) != 0)) {
+      if ((res_unamb == NULL && tc->output_unambiguous != NULL)
+	  || (res_unamb != NULL && strcmp(res_unamb, tc->output_unambiguous) != 0)) {
 	// test case failed...
 	fprintf(stderr, "failed\n");
 	// We want to run all testcases, for purposes of generating a