start topic spec

spec/models/topic_spec.rb

@@ -9,4 +9,20 @@ RSpec.describe Topic, type: :model do
   it { is_expected.to have_many :mappings }
   it { is_expected.to validate_presence_of :permission }
   it { is_expected.to validate_inclusion_of(:permission).in_array Perm::ISSIONS.map(&:to_s) }
+
+  describe 'attachments_json' do
+    let (:attachments) do
+      create_list(:attachment, 1,
+                  file_file_name: 'file_name',
+                  file_content_type: 'text/plain',
+                  file_file_size: '100')
+    end
+    let (:topic) { create(:topic, attachments: attachments) }
+    let(:json) { topic.attachments_json }
+
+    it 'returns correct json' do
+      expect(json.first[:id]).to equal(attachments.first.id)
+      binding.pry
+    end
+  end
 end