Update sentry-ruby/spec/sentry/hub_spec.rb

Co-authored-by: Peter Solnica <peter@solnica.online>

Author: sl0thentr0py

sentry-ruby/spec/sentry/hub_spec.rb

@@ -673,7 +673,7 @@
         expect(subject.current_client).to receive(:buffer_metric_event).and_call_original
         expect do
           subject.capture_metric(name: "test", type: :counter, value: 1)
-        end.to change { subject.current_client.metric_event_buffer.pending_items.count }.by(1)
+        end.to change { subject.current_client.metric_event_buffer.size }.by(1)
       end
     end
   end