Testing if Angular asynchronous function returns a promise fails in Jasmine

I am trying to test if an asynchronous call returns a promise and it is failing. The function I am testing:

findOne: (collection, query) ->
  @find collection, query

where find is function that simply makes a call to $http.post

The spec that is failing: describe "#findOne", () ->

it "should return a promise", () ->
  expect(entitySvc.findOne.then).toBeDefined()

Why is this failing? find is simply returning the httpPromise object returned by $http.post.