Fix query used to calculate number of users over license

The new query use the License period as the range date for the query.
With this change, customers will see a more accurate number on their
Dashboard for the Users Over License section.

ee/app/models/historical_data.rb

@@ -22,7 +22,9 @@ class HistoricalData < ApplicationRecord
     end
 
     def max_historical_user_count
-      HistoricalData.during(1.year.ago..Date.today).maximum(:active_user_count) || 0
+      exp_date = License.current&.expires_at || Date.today
+
+      HistoricalData.during(exp_date.ago(1.year)..exp_date).maximum(:active_user_count) || 0
     end
   end
 end

ee/changelogs/unreleased/rd-8292-maximum-historical-users-should-be-based-on-a-license-s-start-date-not-1-year.yml

+---
+title: Fix query used to calculate number of users over license
+merge_request: 10556
+author:
+type: fixed

ee/spec/models/historical_data_spec.rb

@@ -76,4 +76,39 @@ describe HistoricalData do
       end
     end
   end
+
+  describe '.max_historical_user_count with data outside of the license period' do
+    let!(:license) { create(:license) }
+
+    context 'with stats before the license period' do
+      before do
+        described_class.create!(date: license.starts_at.ago(2.days), active_user_count: 10)
+      end
+
+      it 'ignore those records' do
+        expect(described_class.max_historical_user_count).to eq(0)
+      end
+    end
+
+    context 'with stats after the license period' do
+      before do
+        described_class.create!(date: license.expires_at.in(2.days), active_user_count: 10)
+      end
+
+      it 'ignore those records' do
+        expect(described_class.max_historical_user_count).to eq(0)
+      end
+    end
+
+    context 'with stats inside license period' do
+      before do
+        described_class.create!(date: license.starts_at.in(2.days), active_user_count: 10)
+        described_class.create!(date: license.starts_at.in(5.days), active_user_count: 15)
+      end
+
+      it 'returns max value for active_user_count' do
+        expect(described_class.max_historical_user_count).to eq(15)
+      end
+    end
+  end
 end