diff --git a/spec/perfect_sched_spec.rb b/spec/perfect_sched_spec.rb
index cd5e606..165215e 100644
--- a/spec/perfect_sched_spec.rb
+++ b/spec/perfect_sched_spec.rb
@@ -1,7 +1,7 @@
 require 'spec_helper'
 
 describe PerfectSched do
-  context '.open' do
+  describe '.open' do
     let (:config){ double('config') }
     let (:client){ double('client') }
     let (:schedule_collection){ double('schedule_collection') }
@@ -24,27 +24,51 @@
     end
   end
 
-  context 'cron_time' do
+  describe '.cron_time' do
     it do
-      ts = PerfectSched.cron_time('0 * * * *', 0, nil)
-      expect(ts).not_to be_nil
+      ts = PerfectSched.cron_time('0 * * * *', 1, nil)
+      expect(ts).to eq 3600
     end
     it do
       expect{PerfectSched.cron_time('0 * * * *', 0, 'JST-9')}.to raise_error(ArgumentError)
     end
+    it do
+      ts = PerfectSched.cron_time('0,30 * * * *', 1, nil)
+      expect(ts).to eq 1800
+    end
+    it do
+      ts = PerfectSched.cron_time('*/7 * * * *', 1, nil)
+      expect(ts).to eq 420
+    end
+    it do
+      ts = PerfectSched.cron_time('0-59/7 * * * *', 421, nil)
+      expect(ts).to eq 840
+    end
+    it 'supports @hourly' do
+      ts = PerfectSched.cron_time('@hourly', 1, nil)
+      expect(ts).to eq 3600
+    end
+    it 'supports @daily' do
+      ts = PerfectSched.cron_time('@daily', 1, nil)
+      expect(ts).to eq 86400
+    end
+    it 'supports @monthly' do
+      ts = PerfectSched.cron_time('@monthly', 1, nil)
+      expect(ts).to eq 2678400
+    end
   end
 
-  context '.next_time' do
-    it do
-      ts = PerfectSched.next_time('0 * * * *', 0, nil)
-      expect(ts).not_to be_nil
+  describe '.next_time' do
+    it 'can run hourly cron' do
+      ts = PerfectSched.next_time(' 0 * * * * ', 0, nil)
+      expect(ts).to eq 3600
     end
     it 'calculates 4 years quickly' do
       t = Time.utc(2012,2,29)
       ts = PerfectSched.next_time('0 0 29 2 *', t.to_i, nil)
       expect(ts).to eq(Time.utc(2016,2,29).to_i)
     end
-    it do
+    it 'raises error on unsupported timezone' do
       expect{PerfectSched.next_time('0 * * * *', 0, 'JST-9')}.to raise_error(ArgumentError)
     end
     it 'returns next run time of given time' do