diff --git a/spec/period_spec.rb b/spec/period_spec.rb
index c7441b4..5ecf744 100644
--- a/spec/period_spec.rb
+++ b/spec/period_spec.rb
@@ -4,7 +4,12 @@ describe Crono::Period do
   describe '#description' do
     it 'should return period description' do
       @period = Crono::Period.new(1.week, on: :monday, at: '15:20')
-      expect(@period.description).to be_eql('every 7 days at 15:20 on Monday')
+      expected_description = if ActiveSupport::VERSION::MAJOR >= 5
+          'every 1 week at 15:20 on Monday'
+        else
+          'every 7 days at 15:20 on Monday'
+        end
+      expect(@period.description).to be_eql(expected_description)
     end
   end