Unit testing external library calls in Meteor

gistfile1.coffee

# example class / prototype to test on the client
class ClientThing
  clientFoo: ->
    Meteor.call 'serverFoo', 'bar'
    
# client-side test
describe 'ClientThing', ->
  clientThing = new ClientThing()
  describe '#clientFoo', ->
    it 'calls serverFoo with "bar"', (test) ->
      # use spies to test external library calls
      # https://atmospherejs.com/practicalmeteor/sinon
      sinon.spy(Meteor, 'call')
      
      clientThing.clientFoo()
      test.isTrue Meteor.call.calledWith('bar')
      
      Meteor.call.restore()
      
# on the server, just delegate Meteor.methods to well-tested methods 
class ServerThing
  serverFoo: (message) ->
    console.log message

serverThing = new ServerThing()

Meteor.methods
  serverFoo: (message) ->
    # don't put logic here since it's untested
    serverThing.serverFoo(message)
  
# unit-test ServerThing#serverFoo rather than Meteor.methods