Added a helper method to TimeEntry that will encapsulate the rate API for a TimeEntry.

* TimeEntry#cost will return the amount the TimeEntry costs based on:
** logged hours times the assigned rate amount
** logged hours times the effective project rate for the user
** logged hours times the effective default rate for the user
** 0 if the user has no rates at all

  #1924

init.rb

@@ -2,6 +2,7 @@ require 'redmine'
 
 require 'rate_users_helper_patch'
 require 'rate_sort_helper_patch'
+require 'rate_time_entry_patch'
 
 require 'rate_project_hook'
 

lib/rate_time_entry_patch.rb

@@ -0,0 +1,38 @@
+require_dependency 'time_entry'
+
+module RateTimeEntryPatch
+  def self.included(base) # :nodoc:
+    base.extend(ClassMethods)
+
+    base.send(:include, InstanceMethods)
+
+    # Same as typing in the class 
+    base.class_eval do
+      unloadable # Send unloadable so it will not be unloaded in development
+      belongs_to :rate
+      
+    end
+
+  end
+  
+  module ClassMethods
+    
+  end
+  
+  module InstanceMethods
+    # Returns the current cost of the TimeEntry based on it's rate and hours
+    def cost
+      if self.rate.nil?
+        amount = Rate.amount_for(self.user, self.project, self.spent_on.to_s)
+      else
+        amount = rate.amount
+      end
+
+      return 0.0 if amount.nil?
+      
+      return amount.to_f * hours.to_f
+    end
+  end
+end
+
+TimeEntry.send(:include, RateTimeEntryPatch)

spec/lib/rate_time_entry_patch_spec.rb

@@ -0,0 +1,29 @@
+require File.dirname(__FILE__) + '/../spec_helper'
+
+describe TimeEntry, 'cost' do
+  before(:each) do
+    @user = mock_model(User)
+    @project = mock_model(Project)
+    @date = Date.today.to_s
+    @time_entry = TimeEntry.new({:user => @user, :project => @project, :spent_on => @date, :hours => 10.0})
+  end
+  
+  it 'should return 0.0 if there are no rates for the user' do
+    Rate.should_receive(:amount_for).with(@user, @project, @date).and_return(nil)
+    @time_entry.cost.should eql(0.0)
+  end
+
+  describe 'should return the product of hours by' do
+    it 'the results of Rate.amount_for' do
+      Rate.should_receive(:amount_for).with(@user, @project, @date).and_return(200.0)
+      @time_entry.cost.should eql(200.0 * @time_entry.hours)
+    end
+
+    it 'the assigned rate' do
+      rate = mock_model(Rate, :amount => 100.0)
+      @time_entry.should_receive(:rate).at_least(:twice).and_return(rate)
+      @time_entry.cost.should eql(rate.amount * @time_entry.hours)
+    end
+
+  end
+end