gistfile1.rb

subject do
  Course.create!({:title => 'Test Course', :image => File.open(File.join(Rails.root, 'public', 'images', 'test-image.gif'))})
end 

describe "when an image is attached" do
  it "should respond to an image object" do
    subject.image.class.should == Paperclip::Attachment
  end 

  it "should have a vaild image that's not missing" do
    subject.image.url.should_not match(/missing\.png$/)
  end 

  it "should have the large size set as default" do
    subject.image.url(:large).should == subject.image.url
  end    
end