first pass at a wait_for helper on model

lib/fog/model.rb

@@ -97,6 +97,17 @@ module Fog
       end
     end
 
+    def wait_for(timeout = 600, &block)
+      start = Time.now
+      until instance_eval(&block)
+        if Time.now - start > timeout
+          break
+        end
+        reload
+        sleep(1)
+      end
+    end
+
     private
 
     def collection=(new_collection)

spec/aws/models/ec2/address_spec.rb

@@ -52,9 +52,7 @@ describe 'Fog::AWS::EC2::Address' do
 
     it "should associate with instance to an already saved address" do
       @address.save.should be_true
-      while @instance.state == 'pending'
+      @instance.wait_for { state == 'running' }
-        @instance.reload
-      end
       @address.instance = @instance
       @address.instance_id.should == @instance.id
     end

spec/aws/models/ec2/volume_spec.rb

@@ -49,21 +49,15 @@ describe 'Fog::AWS::EC2::Volume' do
     before(:each) do
       @instance = ec2.instances.create(:image_id => GENTOO_AMI)
       @volume = ec2.volumes.new(:availability_zone => @instance.availability_zone, :size => 1, :device => '/dev/sdz1')
-      while @instance.state == 'pending'
+      @instance.wait_for { state == 'running' }
-        @instance.reload
-      end
     end
 
     after(:each) do
       @instance.destroy
       if @volume.id
-        while ['attaching', 'creating'].include?(@volume.status)
+        @volume.wait_for { status == 'attached' }
-          @volume.reload
-        end
         @volume.instance = nil
-        while ['attached', 'detaching'].include?(@volume.status)
+        @volume.wait_for { status == 'available' }
-          @volume.reload
-        end
         @volume.destroy
       end
     end