How to get property from component when testing?

How can I check component's property value when component doesn't have template? In application the component is extended and template is provided that way.

//my-component.js
export default Ember.Component.extend({
    foo: 'bar'
});

//my-component-test.hbs
integration: true;
test('it renders', function(assert) {
  this.set('foo2', 'foo2');
  this.render(hbs`{{my-component foo=foo2}}`);
  assert.equal(/* ??? */, 'foo2');
});

I am not able to use this.render(hbs'{{#my-component foo=foo2}}{{foo}}{{/my-component}}'); because foo is not yielded. Accessing component directly is not possible either.