How to test logic in joined promises/then - ember.js

Question

I am trying to write a test for an action handler on one of my components. I am stubbing out the save method on one of my models to return a resolved promise using Em.RSVP.Promise.resolve()
in my component, i chain on that promise using then:
return target
.save()
.then(function(){
selected.rollback();
this.sendAction('quicklinkChanged', target);
}.bind(this),this.notify_user_of_persistence_error.bind(this, 'Save As'));
this is a pattern that i use a lot server-side where we use when for our promise library. however, when i do this client-side, i never end up inside the function in the then block so i cannot assert any of the functionality there in my unit tests.
can anyone provide any insight on the best way to do this?

Answer 1

We moved our callbacks out of the method so we could call them separately and verify functionality, or replace them and verify they were called.
Controller Example:
App.IndexController = Em.Controller.extend({
randomProperty: 1,
async: function(fail){
return new Em.RSVP.Promise(function(resolve, reject){
if(fail){
reject('fdas');
}else{
resolve('foo');
}
});
},
doAsyncThing: function(fail){
return this.async(fail).then(this.success.bind(this), this.failure.bind(this));
},
success: function(){
this.set('randomProperty', 2);
},
failure: function(){
this.set('randomProperty', -2);
}
});
Tests
test("async success", function(){
var ic = App.IndexController.createWithMixins();
stop();
ic.doAsyncThing(false).then(function(){
start();
equal(ic.get('randomProperty'), 2);
});
});
test("async fail", function(){
var ic = App.IndexController.createWithMixins();
stop();
ic.doAsyncThing(true).then(function(){
start();
equal(ic.get('randomProperty'), -2);
});
});
test("async success is called", function(){
expect(1);
var ic = App.IndexController.createWithMixins();
ic.success = function(){
ok(true);
};
stop();
ic.doAsyncThing(false).then(function(){
start();
});
});
test("async failure is called", function(){
expect(1);
var ic = App.IndexController.createWithMixins();
ic.failure = function(){
ok(true);
};
stop();
ic.doAsyncThing(true).then(function(){
start();
});
});
test("doAsyncThing returns a promise", function(){
expect(1);
var ic = App.IndexController.createWithMixins();
ok(ic.doAsyncThing(true).then);
});
Example: http://emberjs.jsbin.com/wipo/37/edit