diff --git a/pkg/testutil/testutil.go b/pkg/testutil/testutil.go
index <HASH>..<HASH> 100644
--- a/pkg/testutil/testutil.go
+++ b/pkg/testutil/testutil.go
@@ -22,7 +22,7 @@ import (
 
 // TODO: improve this when we are able to know the schedule or status of target go-routine.
 func WaitSchedule() {
-	time.Sleep(3 * time.Millisecond)
+	time.Sleep(10 * time.Millisecond)
 }
 
 func MustNewURLs(t *testing.T, urls []string) []url.URL {
pkg/testutil: extend wait schedule time to <I>ms

Waiting 3ms is not long enough for schedule to work well. The test suite
may fail once per <I> times in travis due to this. Extend this to <I>ms
to ensure schedule could work. Now it could run <I> times successfully
in travis.