diff --git a/app/models/concerns/build_list_observer.rb b/app/models/concerns/build_list_observer.rb
index fc3596cd7..ef0ec95c1 100644
--- a/app/models/concerns/build_list_observer.rb
+++ b/app/models/concerns/build_list_observer.rb
@@ -9,14 +9,14 @@ module BuildListObserver
 
   def update_average_build_time
     if status_changed?
-      started_at = Time.now if status == self.class::BUILD_STARTED
+      self.started_at = Time.now if status == self.class::BUILD_STARTED
       if [self.class::BUILD_ERROR,
           self.class::SUCCESS,
           self.class::BUILD_CANCELING,
           self.class::TESTS_FAILED,
           self.class::BUILD_CANCELED].include? status
         # stores time interval beetwin build start and finish in seconds
-        duration = current_duration if started_at
+        duration = current_duration if self.started_at
 
         if status == self.class::SUCCESS
           # Update project average build time
diff --git a/spec/models/build_list_observer_spec.rb b/spec/models/build_list_observer_spec.rb
index 78ea54d44..dbedfe1b2 100644
--- a/spec/models/build_list_observer_spec.rb
+++ b/spec/models/build_list_observer_spec.rb
@@ -1,5 +1,15 @@
 require 'spec_helper'
 
 describe BuildListObserver do
-  pending "add some examples to (or delete) #{__FILE__}"
+
+  before { stub_symlink_methods }
+
+  let(:build_list) { FactoryGirl.create(:build_list) }
+
+  it 'updates started_at when build started' do
+    expect(build_list.started_at).to be_nil
+    build_list.start_build
+    expect(build_list.started_at).to_not be_nil
+  end
+
 end