do not show alert if sp help text is a blank string

app/decorators/service_provider_session_decorator.rb

@@ -20,7 +20,7 @@ def remember_device_default
   def custom_alert(section)
     language = I18n.locale.to_s
     alert = sp.help_text.dig(section, language)
-    format(alert, sp_name: sp_name, sp_create_link: sp_create_link) if alert
+    format(alert, sp_name: sp_name, sp_create_link: sp_create_link) if alert.present?
   end
 
   def sp_logo

spec/decorators/service_provider_session_decorator_spec.rb

@@ -66,7 +66,16 @@
     context 'sp does not have a custom alert' do
       let(:sp) { build_stubbed(:service_provider_without_help_text) }
 
-      it 'uses the custom template' do
+      it 'returns nil' do
+        expect(subject.custom_alert('sign_in')).
+          to be_nil
+      end
+    end
+
+    context 'sp has a blank custom alert' do
+      let(:sp) { build_stubbed(:service_provider, :with_blank_help_text) }
+
+      it 'returns nil' do
         expect(subject.custom_alert('sign_in')).
           to be_nil
       end

spec/factories/service_providers.rb

@@ -22,6 +22,15 @@
       end
     end
 
+    trait :with_blank_help_text do
+      friendly_name { 'Test Service Provider with blank help text' }
+      help_text do
+        { 'sign_in': { en: '' },
+          'sign_up': { en: '' },
+          'forgot_password': { en: '' } }
+      end
+    end
+
     factory :service_provider_without_help_text, traits: [:without_help_text]
   end
 end