Merge pull request #1539 from appsignal/fix-delayed-job-hook-spec-order

Fix Delayed Job hook spec order dependency

Author: unflxw

spec/lib/appsignal/hooks/delayed_job_spec.rb

@@ -10,7 +10,13 @@ def self.plugins
           @plugins ||= []
         end
       end)
-      start_agent
+      # Install the hook directly rather than through `start_agent`. Hooks
+      # install once per process and are never reset, so relying on
+      # `start_agent` made "adds the plugin" pass only when this spec was the
+      # first to install the Delayed Job hook -- it saw an empty stubbed worker
+      # (and failed) once any other spec had installed it first. Mirrors the
+      # Shoryuken hook spec.
+      described_class.new.install
     end
 
     describe "#dependencies_present?" do