title: expected Exception but nothing was raised using Rspec
body: <p>I am trying to pass this last test: trying raise an exception I can't make it work
  <strong>My error-log:</strong> </p>
  
  <p>1) VideoSearch find then whole collection of samplers  failing  complains if there is not any RIGHT match
       Failure/Error: expect(vs.find_all_by_title(2343)).to raise_error
         expected Exception but nothing was raised</p>
  
  <p>My code:</p>
  
  <pre><code>class VideoSearch
  
    attr_accessor :title, :samplers
  
    def initialize(params)
      @title = params
      @samplers = []    
    end
  
    def find_all_by_title(title)
      return [] if title.blank?
      Video.where(title: title).first
    end
  
    def find_the_whole_collection(title)  
      if find_all_by_title(title)
        sampler = find_all_by_title(title)
        @samplers = [sampler] #add the video as the first sample
      else
        raise Exception
        return false # it's false if there 's not any match!
      end
    end
  end
  </code></pre>
  
  <p>My spec:</p>
  
  <pre><code>describe 'find then whole collection of samplers ' do
    let(:v1) { v1 = Video.create( title: 2345 ) }
    let(:vs) { VideoSearch.new v1.title }
    let(:sample) { vs.find_all_by_title(v1.title) }
  
    context 'failing' do
      before :each do
        vs.stub(:find_all_by_title).and_return(nil)
      end
  
      it ' complains if there is not any RIGHT match ' do
        expect(vs.find_all_by_title(2343)).to raise_error
      end
    end     
  end
  </code></pre>