def test_intra_similarity_of_empty_cluster(self):
"""
Test that the intra-similarity of an empty cluster is 0.
"""
c = Cluster()
self.assertEqual(0, c.get_intra_similarity())
def test_intra_similarity_of_cluster_with_single_vector(self):
"""
Test that the intra-similarity of a cluster with a single vector is equivalent to that vector's similarity with the cluster.
"""
v = Document("", ['a', 'b'], scheme=TF())
c = Cluster(v)
self.assertEqual(c.similarity(v), c.get_intra_similarity())
def test_intra_similarity_of_cluster(self):
"""
Test that the intra-similarity of a cluster with several vectors is equivalent to the average similarity.
"""
v = [
Document("", ['a', 'b'], scheme=TF()),
Document("", ['a', 'a'], scheme=TF()),
]
c = Cluster(v)
self.assertEqual((c.similarity(v[0]) + c.similarity(v[1])) / 2.,
c.get_intra_similarity())