def test_build_similarity_model(self):
"""Checks that the similarity model is calculated correct."""
ratings = self.get_ratings()
model = Builder.build_similarity_model(ratings)
self.assertIsNotNone(model)
self.assertEqual(len(model), 15)
# item 0 and 2 has identical ratings. Their similarity should therefore be 1.0
self.assertAlmostEqual(model[frozenset({0, 2})], 1.0)
