title: Flask where to read csv data for use in views
body: <p>I'm wondering where the read_csv method should live, in order for it to be accessible by the views in flask, and for optimum unit testing. Ideally for unit tests, I assume I wouldn't want to read the CSV data, so it should be easily mockable?</p>
  
  <p>I'm currently importing data after creating the application, before the views. The views are then accessing the dataframe. Should this be handled elsewhere?</p>
  
  <p>Currently set up like:</p>
  
  <pre><code>application = Flask(__name__)
  
  df = pd.read_csv(filename)
  
  # views below...
  
  </code></pre>