public function testComputeSimilarity()
{
$instance = new KNNModelBuilder(null, new CosineSimilarity());
$source = new ObjectSet(Rating::class);
$destination = new ObjectSet(Rating::class);
$node1 = new FakeNode(1);
$node2 = new FakeNode(2);
$node3 = new FakeNode(3);
$node4 = new FakeNode(4);
$source->add(new Rating(1, $node1->identity()));
$source->add(new Rating(1, $node3->identity()));
$destination->add(new Rating(1, $node2->identity()));
$destination->add(new Rating(1, $node4->identity()));
$similarity = $instance->computeSimilarity($source, $destination);
$this->assertEquals(0.0, $similarity);
}