Feature: Slack integration (#783)

- Integrations architecture
- Slack integration

spec/lib/integrations/slack/incoming_message_builder_spec.rb

@@ -0,0 +1,45 @@
+require 'rails_helper'
+
+describe Integrations::Slack::IncomingMessageBuilder do
+  let(:account) { create(:account) }
+  let(:message_params) { slack_message_stub }
+  let(:verification_params) { slack_url_verification_stub }
+
+  let(:hook) { create(:integrations_hook, account: account, reference_id: message_params[:event][:channel]) }
+  let!(:conversation) { create(:conversation, identifier: message_params[:event][:thread_ts]) }
+
+  describe '#perform' do
+    context 'when url verification' do
+      it 'return challenge code as response' do
+        builder = described_class.new(verification_params)
+        response = builder.perform
+        expect(response[:challenge]).to eql(verification_params[:challenge])
+      end
+    end
+
+    context 'when message creation' do
+      it 'creates message' do
+        messages_count = conversation.messages.count
+        builder = described_class.new(message_params)
+        builder.perform
+        expect(conversation.messages.count).to eql(messages_count + 1)
+      end
+
+      it 'does not create message for invalid event type' do
+        messages_count = conversation.messages.count
+        message_params[:type] = 'invalid_event_type'
+        builder = described_class.new(message_params)
+        builder.perform
+        expect(conversation.messages.count).to eql(messages_count)
+      end
+
+      it 'does not create message for invalid event name' do
+        messages_count = conversation.messages.count
+        message_params[:event][:type] = 'invalid_event_name'
+        builder = described_class.new(message_params)
+        builder.perform
+        expect(conversation.messages.count).to eql(messages_count)
+      end
+    end
+  end
+end