Fix policy tags key error

lib/dfe/analytics/config.rb

@@ -59,7 +59,7 @@ def self.configure(config)
         config.bigquery_hidden_policy_tag       ||= ENV.fetch('BIGQUERY_HIDDEN_POLICY_TAG', nil)
         config.bigquery_policy_tags             ||=
           JSON.parse(ENV.fetch('BIGQUERY_POLICY_TAGS', '{}')).transform_keys(&:underscore).symbolize_keys
-        config.bigquery_policy_tags             ||= { hidden: config.bigquery_hidden_policy_tag } if config.bigquery_hidden_policy_tag.present?
+        config.bigquery_policy_tags = { hidden: config.bigquery_hidden_policy_tag } if config.bigquery_hidden_policy_tag.present? && config.bigquery_policy_tags.blank?
         config.bigquery_retries                 ||= 3
         config.bigquery_timeout                 ||= 120
         config.environment                      ||= ENV.fetch('RAILS_ENV', 'development')

spec/dfe/analytics/config_spec.rb

@@ -32,6 +32,64 @@
       end
     end
 
+    context 'when bigquery_policy_tags is configured' do
+      before do
+        config.bigquery_hidden_policy_tag = 'hidden-policy-tag'
+        config.bigquery_policy_tags = {
+          hidden: 'new-hidden-policy-tag',
+          sensitive_hidden: 'sensitive-hidden-policy-tag'
+        }
+
+        described_class.configure(config)
+      end
+
+      it 'uses the configured policy tags' do
+        expect(config.bigquery_policy_tags).to eq(
+          hidden: 'new-hidden-policy-tag',
+          sensitive_hidden: 'sensitive-hidden-policy-tag'
+        )
+      end
+    end
+
+    context 'when bigquery_policy_tags is empty and bigquery_hidden_policy_tag is configured' do
+      before do
+        config.bigquery_hidden_policy_tag = 'hidden-policy-tag'
+        config.bigquery_policy_tags = {}
+
+        described_class.configure(config)
+      end
+
+      it 'falls back to the legacy hidden policy tag' do
+        expect(config.bigquery_policy_tags).to eq(
+          hidden: 'hidden-policy-tag'
+        )
+      end
+    end
+
+    context 'when neither policy tag configuration is provided' do
+      before do
+        config.bigquery_hidden_policy_tag = nil
+        config.bigquery_policy_tags = {}
+
+        described_class.configure(config)
+      end
+
+      it 'leaves bigquery_policy_tags empty' do
+        expect(config.bigquery_policy_tags).to eq({})
+      end
+    end
+
+    context 'when database_events_enabled is false' do
+      before do
+        config.database_events_enabled = false
+        described_class.configure(config)
+      end
+
+      it 'preserves the configured value' do
+        expect(config.database_events_enabled).to eq(false)
+      end
+    end
+
     context 'when azure_federated_auth is true' do
       before do
         # Stub all expected ENV.fetch calls used by .configure