diff --git a/src/copy_dir.rs b/src/copy_dir.rs
index 2f83bcb..be1edb7 100644
--- a/src/copy_dir.rs
+++ b/src/copy_dir.rs
@@ -296,8 +296,12 @@ mod tests {
     }
 
     fn assert_dirs_same<P: AsRef<Path>>(a: P, b: P) {
-        let mut wa = walkdir::WalkDir::new(a.as_ref()).into_iter();
-        let mut wb = walkdir::WalkDir::new(b.as_ref()).into_iter();
+        let mut wa = walkdir::WalkDir::new(a.as_ref())
+            .sort_by_file_name()
+            .into_iter();
+        let mut wb = walkdir::WalkDir::new(b.as_ref())
+            .sort_by_file_name()
+            .into_iter();
 
         loop {
             let o_na = wa.next();