title: Simplecov coverage report seems to miss certain lines
body: <p>Just after some clarification on how simplecov determines if a line has been exercised by a test.</p>
  
  <p>I have the following method:</p>
  
  <pre><code>def over?
    end_at &lt; Time.zone.now
  end
  </code></pre>
  
  <p>in which end_at is an ActiveRecord attribute on the object.</p>
  
  <p>Which is exercised in the following spec:</p>
  
  <pre><code>describe CalendarEntry do
    it 'can determine that an event has ended' do
      @entry.end_at = 1.day.ago
      @entry.over?.should be_true
    end
  end
  </code></pre>
  
  <p>After running the spec with coverage, it shows the following result:</p>
  
  <p><img src="https://i.stack.imgur.com/2S7DW.png" alt="coverage report"></p>
  
  <p>I've run the test in debug mode with a break point on this line and confirmed that the spec is indeed hitting it.</p>
  
  <p>This isn't isolated to just this line in this method, every line that includes the use of an ActiveRecord associated getter is shown as not covered. Could be coincidence, but seems a bit odd.</p>
  
  <p>Environment: ruby 1.9.3-p327 (mri), rails 3.2.8, simplecov 0.7.1, rspec 2.10.0.</p>
  
  <p>Any ideas on why simplecov thinks it's not covered?</p>