Diagnose when test features are missing
diff --git a/tests/test_asyncness.rs b/tests/test_asyncness.rs
index b73537b..78bee8c 100644
--- a/tests/test_asyncness.rs
+++ b/tests/test_asyncness.rs
@@ -6,11 +6,11 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![cfg(all(feature = "extra-traits", feature = "full"))]
-
 extern crate proc_macro2;
 extern crate syn;
 
+mod features;
+
 use proc_macro2::Span;
 use syn::punctuated::Punctuated;
 use syn::{Block, Expr, ExprBlock, ExprClosure, FnDecl, Ident, ItemFn, ReturnType, Visibility};