[#2844] Added an API to get the total number of billable and overhead hours.

* Added Issue#billable_time_spent
* Added Issue#overhead_time_spent
* Added specs

spec/lib/overhead_issue_patch_spec.rb

@@ -0,0 +1,80 @@
+require File.dirname(__FILE__) + '/../spec_helper'
+
+def mock_time_entry(hours, billable)
+  mock_model(TimeEntry, :hours => hours.to_f, :billable? => billable)
+end
+
+describe Issue, '#billable_time_spent' do
+  it 'should total the billable time entries' do
+    time_entries = [mock_time_entry(12, true),
+                    mock_time_entry(13, true)]
+    
+    issue = Issue.new
+    issue.should_receive(:time_entries).and_return(time_entries)
+    issue.billable_time_spent.should eql(25.0)
+  end
+  
+  it 'should not include overhead time entries' do
+    time_entries = [mock_time_entry(12, true),
+                    mock_time_entry(13, true),
+                    mock_time_entry(20, false),
+                    mock_time_entry(40, false)]
+    
+    issue = Issue.new
+    issue.should_receive(:time_entries).and_return(time_entries)
+    issue.billable_time_spent.should eql(25.0)
+  end
+
+  it 'should round to the tenths place' do
+    time_entries = [mock_time_entry(20, true),
+                    mock_time_entry(13.333333, true)]
+    
+    issue = Issue.new
+    issue.should_receive(:time_entries).and_return(time_entries)
+    issue.billable_time_spent.should eql(33.3)
+
+  end
+
+  it 'should return 0 if there are no time entries' do
+    issue = Issue.new
+    issue.billable_time_spent.should eql(0)
+  end
+end
+
+describe Issue, '#overhead_time_spent' do
+  it 'should total the overhead time entries' do
+    time_entries = [mock_time_entry(12, false),
+                    mock_time_entry(13, false)]
+    
+    issue = Issue.new
+    issue.should_receive(:time_entries).and_return(time_entries)
+    issue.overhead_time_spent.should eql(25.0)
+  end
+  
+  it 'should not include billable time entries' do
+    time_entries = [mock_time_entry(12, true),
+                    mock_time_entry(13, true),
+                    mock_time_entry(20, false),
+                    mock_time_entry(40, false)]
+    
+    issue = Issue.new
+    issue.should_receive(:time_entries).and_return(time_entries)
+    issue.overhead_time_spent.should eql(60.0)
+  end
+
+  it 'should round to the tenths place' do
+    time_entries = [mock_time_entry(20, false),
+                    mock_time_entry(13.333333, false)]
+    
+    issue = Issue.new
+    issue.should_receive(:time_entries).and_return(time_entries)
+    issue.overhead_time_spent.should eql(33.3)
+
+  end
+
+  it 'should return 0 if there are no time entries' do
+    issue = Issue.new
+    issue.overhead_time_spent.should eql(0)
+  end
+end
+