diff --git a/integration/access_log_test.go b/integration/access_log_test.go
index dec8071b1..175edeace 100644
--- a/integration/access_log_test.go
+++ b/integration/access_log_test.go
@@ -97,7 +97,7 @@ func CheckAccessLogFormat(c *check.C, line string, i int) {
 	tokens, err := shellwords.Parse(line)
 	c.Assert(err, checker.IsNil)
 	c.Assert(tokens, checker.HasLen, 14)
-	c.Assert(tokens[6], checker.Matches, `^\d{3}$`)
+	c.Assert(tokens[6], checker.Matches, `^(-|\d{3})$`)
 	c.Assert(tokens[10], checker.Equals, fmt.Sprintf("%d", i+1))
 	c.Assert(tokens[11], checker.HasPrefix, "frontend")
 	c.Assert(tokens[12], checker.HasPrefix, "http://127.0.0.1:808")