title: Rspec: test number of rows in CSV output
body: <p>In Rspec how do I test the number of rows that are in a CSV file?</p>
  
  <p>I have created a CSV file in a mutation. I am able to test the output of the CSV by checking if certain text is included. However, I would like to be able to test the number of rows that are in the output.</p>
  
  <p>Please find an <em>example</em> of what I have tested so far below which passes:</p>
  
  <pre><code>describe "#execute" do
  
      it "creates a CSV for the specified content" do
        outcome = mutation.run(mutation_params)
  
        expect(outcome.result).to include("Name")
      end
    end
  </code></pre>