diff --git a/spec/couchrest/core/database_spec.rb b/spec/couchrest/core/database_spec.rb
index 57dc2a4..6a548a9 100644
--- a/spec/couchrest/core/database_spec.rb
+++ b/spec/couchrest/core/database_spec.rb
@@ -258,7 +258,9 @@ describe CouchRest::Database do
       @file.close
     end
     it "should save the attachment to a new doc" do
-      r = @db.put_attachment({'_id' => 'attach-this'}, 'couchdb.png', image = @file.read, {:content_type => 'image/png'})
+      image = @file.read
+      image.force_encoding('ASCII-8BIT') if image.respond_to?(:force_encoding)
+      r = @db.put_attachment({'_id' => 'attach-this'}, 'couchdb.png', image, {:content_type => 'image/png'})
       r['ok'].should == true
       doc = @db.get("attach-this")
       attachment = @db.fetch_attachment(doc,"couchdb.png")