How do I call inputs and buttons in my EmberJS acceptance tests?

This is maddening, as there is little to no help on google/the internet for this. http://ift.tt/1MrQsDS is also not very helpful, even though it tries. I am basically learning this from scratch. I know a modest amount of HTML, handlebars, and javascript, but emphasis on the modest.

Here is my template, much of it is copied code from my architect's design who doesn't have time to help me :

<form {{action "login" on="submit"}} class="col-md-4 col-md-offset-4">
    {{#if loginFailed}}
    <div class="alert">Invalid username or password.</div>
  {{/if}}

  <div class="form-group">
    <label for="inputEmail">Email address</label>
    {{input value=username type="email" class="form-control" id="inputEmail1" placeholder="Email"}}
  </div>

  <div class="form-group">
    <label for="inputPassword">Password</label>
    {{input value=password type="password" class="form-control" id="inputPassword" placeholder="Password"}}
  </div>

  <button type="submit" class="btn btn-default" disabled={{isProcessing}}>Log in!</button>
</form>

Note the application runs correctly (I'm able to generate a login screen which connects to my local database, and I am able to log in correctly when the credentials are correct and not login when they aren't).

There is also a large .js file for the route which has an ajax call and corresponding promise from it, which I can sort of understand, but bottom line, it works :

import Ember from 'ember';
import ajax from 'ic-ajax';

export default Ember.Route.extend({

    loginFailed: false,
  isProcessing: false,

    beforeModel: function(){
        this.store.unloadAll('security-setting');
        this.store.unloadAll('org');

        var user = this.modelFor('application').user;
        user.setProperties({email: '', auth: ''});
    },

  actions: {
    login: function() {
        this.setProperties({
          loginFailed: false,
          isProcessing: true
        });
        var _this = this;

        ajax({
            url: _this.modelFor('application').url + '/signin.json/',
            type: 'post',
            data: {session: {email: this.controller.get("username"), password: this.controller.get("password")}},
      }).then(
                function(result) {
                  // proprietary stuff, it all works
                },
                function(error){
                    alert(error.jqXHR.responseText);
                    this.set('isProcessing', false);
                _this.set("loginFailed", true);
                }
            );


      },
  },

  reset: function() {
    this.set('isProcessing', false);
    this.controller.set('password', '');
    this.controller.set('username', '');
  }
});

Here is the acceptance test I am trying to write :

import Ember from 'ember';
import { module, test } from 'qunit';
import startApp from 'ember-super-user/tests/helpers/start-app';

module('Acceptance | login', {
  beforeEach: function() {
    this.application = startApp();
  },

  afterEach: function() {
    Ember.run(this.application, 'destroy');
  }
});

test('visiting /login and fail a login attempt', function(assert) {
  visit('/login');
  fillIn('input.username', 'insert-username-here');
  fillIn('input.password', 'insert-password-here');
  click('button.submit');

  // I know this assert is wrong but I haven't even gotten this far yet so I'm     // not thinking about it; basically what happens is a popup appears and says    // wrong-username-or-password-etc
  andThen(function() {
    assert.equal(currentURL(), '/login');
  });
});

Execution dies on the fillIn lines of code. I really don't know what to do here, I've tried all combinations of 'input.username', 'input.inputEmail1', 'input.inputEmail'... I'm just not sure what I'm supposed to do, at all. I'm also pretty sure that 'button.submit' will not just magically work either. Then, I know I'll be even more lost when I try to fill in the andThen promise to acknowledge the fact that a popup appeared saying wrong-password-etc.

Please help; thanks very much for your time.