diff --git a/src/book/bookconfig_test.rs b/src/book/bookconfig_test.rs
index 34122628..61cfa6a9 100644
--- a/src/book/bookconfig_test.rs
+++ b/src/book/bookconfig_test.rs
@@ -1,4 +1,4 @@
-#[cfg(test)]
+#![cfg(test)]
 
 use std::path::Path;
 use serde_json;