diff --git a/tests/flags.rs b/tests/flags.rs
index fba5eb38..69d79f6a 100644
--- a/tests/flags.rs
+++ b/tests/flags.rs
@@ -118,6 +118,7 @@ fn verbose_mode() {
     #[cfg(feature = "rayon")]
     rayon::ThreadPoolBuilder::new()
         .start_handler(move |_| thread_init())
+        .num_threads(rayon::current_num_threads() + 1)
         .build()
         .unwrap()
         .install(move || rayon::spawn(thread_exec));