Add first pass coverage for `AnnualReport` class (#31704)

spec/lib/annual_report_spec.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe AnnualReport do
+  describe '#generate' do
+    subject { described_class.new(account, Time.zone.now.year) }
+
+    let(:account) { Fabricate :account }
+
+    it 'builds a report for an account' do
+      expect { subject.generate }
+        .to change(GeneratedAnnualReport, :count).by(1)
+    end
+  end
+end