How can I get Jasmine to wait for a Meteor method call to complete without resorting to setTimeout?

I'm writing a client integration test to verify a particular user can change roles on other users via the front-end.

it('should be able to change user roles', function(done) {
    var newUser = Meteor.users.findOne({ emails: { $elemMatch: { address: 'devon@radworks.io' } } });
    $('#user-' + newUser._id + '-roles').val('manage-users').change();
    expect(Roles.userIsInRole(newUser, 'manage-users')).toBe(true);
    expect(Roles.userIsInRole(newUser, 'edit-any')).toBe(false);
    done();
});

The change() event is bound to a function that calls a Meteor method to change the roles.

Template.users.events({
  'change .change-roles': function(e) {
    e.preventDefault();
    var newRoles = $(e.target).val() || [];
    Meteor.call('changeRoles', this._id, newRoles);
  }
});

Here's the Meteor method:

Meteor.methods({
  'changeRoles': function (userToChangeId, newRoles) {
    check(this.userId, String);
    check(userToChangeId, String);

    if (!Roles.userIsInRole(this.userId, 'manage-users')) {
      throw new Meteor.Error('Not authorized to manage user roles');
    }

    // If the current logged in user is the one we are changing, add manage-users back to
    // the list of new roles.
    if (userToChangeId === this.userId) {
      newRoles.push('manage-users');
    }

    if (Meteor.users.find(userToChangeId).count() !== 1) {
      throw new Meteor.Error('invalid', 'Unable to find the user you want to change');
    }

    Roles.setUserRoles(userToChangeId, newRoles);
  }
});

My test fails even though I can run the test manually and get the expected results. I believe it fails because Roles.setUserRoles has not yet completed by the time I run the expect in my test. I want to wait on the method to complete without simply putting the expect behind a setTimeout. What's the pattern for doing this?