improve mock

Author: johha

spec/unit/lib/delayed_job_plugins/delayed_jobs_metrics_spec.rb

@@ -1,12 +1,12 @@
-require 'db_spec_helper'
+require 'spec_helper'
 
 RSpec.describe DelayedJobMetrics::Plugin do
-  let(:prometheus) { instance_double(VCAP::CloudController::Metrics::PrometheusUpdater) }
   let(:worker) { instance_double(Delayed::Worker, name: 'test_worker') }
 
   before do
+    @prometheus = instance_double(VCAP::CloudController::Metrics::PrometheusUpdater)
     allow(CloudController::DependencyLocator.instance).to receive(:cc_worker_prometheus_updater).and_return(prometheus)
-    allow(prometheus).to receive(:update_histogram_metric)
+    allow(@prometheus).to receive(:update_histogram_metric)
   end
 
   it 'loads the plugin' do