diff --git a/lib/action_subscriber/rspec.rb b/lib/action_subscriber/rspec.rb
index <HASH>..<HASH> 100644
--- a/lib/action_subscriber/rspec.rb
+++ b/lib/action_subscriber/rspec.rb
@@ -46,10 +46,10 @@ module ActionSubscriber
     def mock_subscriber(opts = {})
       encoded_payload = opts.fetch(:encoded_payload) { double('encoded payload').as_null_object }
       header = opts.fetch(:header) { double('header').as_null_object }
-      payload = opts.fetch(:payload) { double('payload').as_null_object }
       subscriber_class = opts.fetch(:class) { described_class }
 
       env = Middleware::Env.new(subscriber_class, header, encoded_payload)
+      env.payload = opts.fetch(:payload) { double('payload').as_null_object }
 
       return subscriber_class.new(env)
     end
Store payload in the env when mocking subscribers

In the RSpec helpers, we need to store the payload (when given) in the
env so it's available in the subscribers since we're not going through
the decoder middleware.