Testing a Yield with Jasmine that uses Mongo / Mongoose

Question

First here's the db.js

// Load Mongoose interface
var mongoose = require('mongoose');

// Get config file for SQL connection
var connection = mongoose.connect('localhost/test');

// Return connection
module.exports = connection;

Here's the Todo Model, todo.js

// Get mongoose object
var db = require('../lib/db');

// Prepare schema
var schema = new db.Schema(
{
    name:           String,
    description:    String
} );

// Return model with schema linked to collection
module.exports = db.model( 'tests', schema );

And here's the route 'update.js' that executes the query against the model

// Require todo model
var Todo = require('../models/todo');

module.exports = function *() {
  // Get request body
  var input = this.request.body;

  // Update todo item with given input ID
  yield Todo.update( {_id: input.id}, {
    name: input.name,
    description: input.description,
    created_on: new Date(input.created_on),
    updated_on: new Date()});

  // Redirect to index
  this.redirect('/');
};

The middle ware is koa.js btw. the route being

 app.use(route.post('/todo/update', require('./routes/update')));

Question: How do I write a test against 'update.js' that has *() and the yield statement ? What would the Jasmine fake/spy be ?

Any other testing framework will be considered not just Jasmine