Improve usage_data monthly specs

spec/lib/gitlab/usage_data_spec.rb

@@ -591,9 +591,21 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
 
   describe '.system_usage_data_monthly' do
     let_it_be(:project) { create(:project) }
-    let!(:ud) { build(:usage_data) }
 
     before do
+      project = create(:project)
+      env = create(:environment)
+      create(:package, project: project, created_at: 3.days.ago)
+      create(:package, created_at: 2.months.ago, project: project)
+
+      [3, 31].each do |n|
+        deployment_options = { created_at: n.days.ago, project: env.project, environment: env }
+        create(:deployment, :failed, deployment_options)
+        create(:deployment, :success, deployment_options)
+        create(:project_snippet, project: project, created_at: n.days.ago)
+        create(:personal_snippet, created_at: n.days.ago)
+      end
+
       stub_application_setting(self_monitoring_project: project)
 
       for_defined_days_back do
@@ -609,10 +621,10 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
       expect(counts_monthly[:deployments]).to eq(2)
       expect(counts_monthly[:successful_deployments]).to eq(1)
       expect(counts_monthly[:failed_deployments]).to eq(1)
-      expect(counts_monthly[:snippets]).to eq(3)
+      expect(counts_monthly[:snippets]).to eq(2)
       expect(counts_monthly[:personal_snippets]).to eq(1)
-      expect(counts_monthly[:project_snippets]).to eq(2)
-      expect(counts_monthly[:packages]).to eq(3)
+      expect(counts_monthly[:project_snippets]).to eq(1)
+      expect(counts_monthly[:packages]).to eq(1)
       expect(counts_monthly[:promoted_issues]).to eq(1)
     end
   end