diff --git a/nemu/tests/expr_test.c b/nemu/tests/expr_test.c
index efb89d0..bb91ae2 100644
--- a/nemu/tests/expr_test.c
+++ b/nemu/tests/expr_test.c
@@ -79,6 +79,10 @@ START_TEST(test_expr_random_100) {
   fclose(fp);
 
   int ret = system("gcc /tmp/.code.c -Werror=div-by-zero -o /tmp/.expr");
+  if(ret == -1) {
+    // Probably devide by zero. Skip
+    goto clean_up;
+  }
   ck_assert_msg(!ret, "system ret: %d, error: %s", ret, strerror(ret));
 
   fp = popen("/tmp/.expr", "r");
@@ -97,6 +101,7 @@ START_TEST(test_expr_random_100) {
 
   ck_assert_msg(addr == reference, "\n\tbuf = %s\n\taddr = %u, reference = %u\n", buf, addr, reference);
 
+clean_up:
   while(buf_ptr != buf + buf_start_pos) {
     *(--buf_ptr) = '\0';
   }