diff --git a/lib/fog/openstack/requests/compute/get_snapshot_details.rb b/lib/fog/openstack/requests/compute/get_snapshot_details.rb
index 5e4355dd1..45e854274 100644
--- a/lib/fog/openstack/requests/compute/get_snapshot_details.rb
+++ b/lib/fog/openstack/requests/compute/get_snapshot_details.rb
@@ -16,7 +16,7 @@ module Fog
 
       class Mock
 
-        def get_snapshot_details(detailed=true)
+        def get_snapshot_details(snapshot_id)
           response = Excon::Response.new
           response.status = 200
           response.body = {