Improve DelayAgent

- Reduce repeated calls to interpolated() and hash reference
- Improve tests and cover the last fix

app/models/agents/delay_agent.rb

@@ -72,15 +72,16 @@ def working?
 
     def receive(incoming_events)
       incoming_events.each do |event|
-        memory['event_ids'] ||= []
-        memory['event_ids'] << event.id
-        if memory['event_ids'].length > interpolated['max_events'].to_i
+        event_ids = memory['event_ids'] || []
+        event_ids << event.id
+        if event_ids.length > interpolated['max_events'].to_i
           if options['keep'] == 'newest'
-            memory['event_ids'].shift
+            event_ids.shift
           else
-            memory['event_ids'].pop
+            event_ids.pop
           end
         end
+        memory['event_ids'] = event_ids
       end
     end
 
@@ -93,8 +94,10 @@ def check
         events = sort_events(events)
       end
 
-      if interpolated['max_emitted_events'].present? and interpolated['max_emitted_events'].to_i < events.length
-        events[interpolated['max_emitted_events'].to_i..] = []
+      max_emitted_events = interpolated['max_emitted_events'].presence&.to_i
+
+      if max_emitted_events&.< events.length
+        events[max_emitted_events..] = []
       end
 
       interval = (options['emit_interval'].presence&.to_f || 0).clamp(0..)

spec/models/agents/delay_agent_spec.rb

@@ -117,11 +117,10 @@ def create_event(value)
       expect {
         agent.check
       }.to change { agent.events.count }.by(2)
-
-      events = agent.events.reorder(id: :desc)
-      expect(events.first.payload).to eq third_event.payload
-      expect(events.second.payload).to eq second_event.payload
-
+      expect(agent.events.take(2).map(&:payload)).to eq [
+        third_event,
+        second_event,
+      ].map(&:payload)
       expect(agent.memory['event_ids']).to eq []
     end
 
@@ -143,9 +142,10 @@ def create_event(value)
           agent.check
         }.to change { agent.events.count }.by(2)
 
-        events = agent.events.reorder(id: :desc)
-        expect(events.first.payload).to eq second_event.payload
-        expect(events.second.payload).to eq third_event.payload
+        expect(agent.events.take(2).map(&:payload)).to eq [
+          second_event,
+          third_event,
+        ].map(&:payload)
 
         expect(agent.memory['event_ids']).to eq []
       end
@@ -156,17 +156,25 @@ def create_event(value)
         agent.update!(options: agent.options.merge('max_emitted_events' => 1))
       end
 
-      it "re-emits max_emitted_events and clears just them from the memory" do
+      it "re-emits max_emitted_events per run" do
         agent.receive([first_event, second_event, third_event])
         expect(agent.memory['event_ids']).to eq [second_event.id, third_event.id]
 
         expect {
           agent.check
         }.to change { agent.events.count }.by(1)
-
-        events = agent.events.reorder(id: :desc)
+        expect(agent.events.take.payload).to eq second_event.payload
         expect(agent.memory['event_ids']).to eq [third_event.id]
-        expect(events.first.payload).to eq second_event.payload
+
+        expect {
+          agent.check
+        }.to change { agent.events.count }.by(1)
+        expect(agent.events.take.payload).to eq third_event.payload
+        expect(agent.memory['event_ids']).to eq []
+
+        expect {
+          agent.check
+        }.not_to(change { agent.events.count })
       end
     end
   end