How do I test this?

outfitCollectionView.js

window.app.OutFitCollectionView = Backbone.View.extend({
  
  // redacted code for brevity...

  render: function() {
    this.collection.each(this.renderOutfit);
    // redacted code for brevity...
    return this;
  },

  renderOutfit: function(outfit) {
    var view = new window.app.OutfitView({model: outfit});
    this.$el.append(view.render().el);
  }
});


/*

  My test is that calling `renderOutfit` should instantiate a new OutfitView and append it's el to 
  the collectionView's el.

  I'd like to spy on the OutfitView's el and have it return some simple markup I can than check is 
  the collectionView's $el but spys are for functions, not properties.

  

*/