diff --git a/spec/model_spec.rb b/spec/model_spec.rb
index f0000bf..19755bd 100644
--- a/spec/model_spec.rb
+++ b/spec/model_spec.rb
@@ -5,6 +5,7 @@ describe Redistat::Model do
   include Redistat::Database
   
   before(:each) do
+    @time = Time.utc(2010, 8, 28, 12, 0, 0)
     ModelHelper1.redis.flushdb
     ModelHelper2.redis.flushdb
     ModelHelper3.redis.flushdb
@@ -43,28 +44,28 @@ describe Redistat::Model do
   end
   
   it "should store and fetch stats" do
-    ModelHelper1.store("sheep.black", {:count => 6, :weight => 461}, 4.hours.ago)
-    ModelHelper1.store("sheep.black", {:count => 2, :weight => 156})
+    ModelHelper1.store("sheep.black", {:count => 6, :weight => 461}, @time.hours_ago(4))
+    ModelHelper1.store("sheep.black", {:count => 2, :weight => 156}, @time)
     
-    stats = ModelHelper1.fetch("sheep.black", 2.hours.ago, 1.hour.from_now)
+    stats = ModelHelper1.fetch("sheep.black", @time.hours_ago(2), @time.hours_since(1))
     stats.total["count"].should == 2
     stats.total["weight"].should == 156
     stats.first.should == stats.total
     
-    stats = ModelHelper1.fetch("sheep.black", 5.hours.ago, 1.hour.from_now)
+    stats = ModelHelper1.fetch("sheep.black", @time.hours_ago(5), @time.hours_since(1))
     stats.total[:count].should == 8
     stats.total[:weight].should == 617
     stats.first.should == stats.total
     
-    ModelHelper1.store("sheep.white", {:count => 5, :weight => 393}, 4.hours.ago)
-    ModelHelper1.store("sheep.white", {:count => 4, :weight => 316})
+    ModelHelper1.store("sheep.white", {:count => 5, :weight => 393}, @time.hours_ago(4))
+    ModelHelper1.store("sheep.white", {:count => 4, :weight => 316}, @time)
     
-    stats = ModelHelper1.fetch("sheep.white", 2.hours.ago, 1.hour.from_now)
+    stats = ModelHelper1.fetch("sheep.white", @time.hours_ago(2), @time.hours_since(1))
     stats.total[:count].should == 4
     stats.total[:weight].should == 316
     stats.first.should == stats.total
     
-    stats = ModelHelper1.fetch("sheep.white", 5.hours.ago, 1.hour.from_now)
+    stats = ModelHelper1.fetch("sheep.white", @time.hours_ago(5), @time.hours_since(1))
     stats.total[:count].should == 9
     stats.total[:weight].should == 709
     stats.first.should == stats.total
@@ -73,31 +74,31 @@ describe Redistat::Model do
   it "should connect to different Redis servers on a per-model basis" do
     ModelHelper3.redis.client.db.should == 14
     
-    ModelHelper3.store("sheep.black", {:count => 6, :weight => 461}, 4.hours.ago)
-    ModelHelper3.store("sheep.black", {:count => 2, :weight => 156})
+    ModelHelper3.store("sheep.black", {:count => 6, :weight => 461}, @time.hours_ago(4))
+    ModelHelper3.store("sheep.black", {:count => 2, :weight => 156}, @time)
     
     db.keys("*").should be_empty
     ModelHelper1.redis.keys("*").should be_empty
     db("ModelHelper3").keys("*").should have(5).items
     ModelHelper3.redis.keys("*").should have(5).items
     
-    stats = ModelHelper3.fetch("sheep.black", 2.hours.ago, 1.hour.from_now)
+    stats = ModelHelper3.fetch("sheep.black", @time.hours_ago(2), @time.hours_since(1))
     stats.total["count"].should == 2
     stats.total["weight"].should == 156
-    stats = ModelHelper3.fetch("sheep.black", 5.hours.ago, 1.hour.from_now)
+    stats = ModelHelper3.fetch("sheep.black", @time.hours_ago(5), @time.hours_since(1))
     stats.total[:count].should == 8
     stats.total[:weight].should == 617
     
     ModelHelper3.connect_to(:port => 8379, :db => 13)
     ModelHelper3.redis.client.db.should == 13
     
-    stats = ModelHelper3.fetch("sheep.black", 5.hours.ago, 1.hour.from_now)
+    stats = ModelHelper3.fetch("sheep.black", @time.hours_ago(5), @time.hours_since(1))
     stats.total.should == {}
     
     ModelHelper3.connect_to(:port => 8379, :db => 14)
     ModelHelper3.redis.client.db.should == 14
     
-    stats = ModelHelper3.fetch("sheep.black", 5.hours.ago, 1.hour.from_now)
+    stats = ModelHelper3.fetch("sheep.black", @time.hours_ago(5), @time.hours_since(1))
     stats.total[:count].should == 8
     stats.total[:weight].should == 617
   end