diff --git a/src/writer_spec.rs b/src/writer_spec.rs
index 6533af1e..236817f1 100644
--- a/src/writer_spec.rs
+++ b/src/writer_spec.rs
@@ -1,4 +1,5 @@
 use std::io;
+use std::ascii::AsciiExt;
 use types::ZipFile;
 use result::ZipResult;
 use spec;