157 lines
5.6 KiB
Python
157 lines
5.6 KiB
Python
# Natural Language Toolkit: Language Model Unit Tests
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#
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# Copyright (C) 2001-2023 NLTK Project
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# Author: Ilia Kurenkov <ilia.kurenkov@gmail.com>
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# URL: <https://www.nltk.org/>
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# For license information, see LICENSE.TXT
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import unittest
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from collections import Counter
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from timeit import timeit
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from nltk.lm import Vocabulary
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class NgramModelVocabularyTests(unittest.TestCase):
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"""tests Vocabulary Class"""
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@classmethod
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def setUpClass(cls):
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cls.vocab = Vocabulary(
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["z", "a", "b", "c", "f", "d", "e", "g", "a", "d", "b", "e", "w"],
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unk_cutoff=2,
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)
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def test_truthiness(self):
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self.assertTrue(self.vocab)
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def test_cutoff_value_set_correctly(self):
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self.assertEqual(self.vocab.cutoff, 2)
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def test_unable_to_change_cutoff(self):
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with self.assertRaises(AttributeError):
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self.vocab.cutoff = 3
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def test_cutoff_setter_checks_value(self):
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with self.assertRaises(ValueError) as exc_info:
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Vocabulary("abc", unk_cutoff=0)
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expected_error_msg = "Cutoff value cannot be less than 1. Got: 0"
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self.assertEqual(expected_error_msg, str(exc_info.exception))
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def test_counts_set_correctly(self):
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self.assertEqual(self.vocab.counts["a"], 2)
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self.assertEqual(self.vocab.counts["b"], 2)
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self.assertEqual(self.vocab.counts["c"], 1)
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def test_membership_check_respects_cutoff(self):
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# a was seen 2 times, so it should be considered part of the vocabulary
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self.assertTrue("a" in self.vocab)
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# "c" was seen once, it shouldn't be considered part of the vocab
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self.assertFalse("c" in self.vocab)
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# "z" was never seen at all, also shouldn't be considered in the vocab
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self.assertFalse("z" in self.vocab)
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def test_vocab_len_respects_cutoff(self):
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# Vocab size is the number of unique tokens that occur at least as often
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# as the cutoff value, plus 1 to account for unknown words.
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self.assertEqual(5, len(self.vocab))
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def test_vocab_iter_respects_cutoff(self):
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vocab_counts = ["a", "b", "c", "d", "e", "f", "g", "w", "z"]
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vocab_items = ["a", "b", "d", "e", "<UNK>"]
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self.assertCountEqual(vocab_counts, list(self.vocab.counts.keys()))
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self.assertCountEqual(vocab_items, list(self.vocab))
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def test_update_empty_vocab(self):
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empty = Vocabulary(unk_cutoff=2)
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self.assertEqual(len(empty), 0)
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self.assertFalse(empty)
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self.assertIn(empty.unk_label, empty)
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empty.update(list("abcde"))
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self.assertIn(empty.unk_label, empty)
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def test_lookup(self):
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self.assertEqual(self.vocab.lookup("a"), "a")
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self.assertEqual(self.vocab.lookup("c"), "<UNK>")
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def test_lookup_iterables(self):
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self.assertEqual(self.vocab.lookup(["a", "b"]), ("a", "b"))
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self.assertEqual(self.vocab.lookup(("a", "b")), ("a", "b"))
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self.assertEqual(self.vocab.lookup(("a", "c")), ("a", "<UNK>"))
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self.assertEqual(
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self.vocab.lookup(map(str, range(3))), ("<UNK>", "<UNK>", "<UNK>")
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)
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def test_lookup_empty_iterables(self):
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self.assertEqual(self.vocab.lookup(()), ())
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self.assertEqual(self.vocab.lookup([]), ())
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self.assertEqual(self.vocab.lookup(iter([])), ())
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self.assertEqual(self.vocab.lookup(n for n in range(0, 0)), ())
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def test_lookup_recursive(self):
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self.assertEqual(
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self.vocab.lookup([["a", "b"], ["a", "c"]]), (("a", "b"), ("a", "<UNK>"))
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)
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self.assertEqual(self.vocab.lookup([["a", "b"], "c"]), (("a", "b"), "<UNK>"))
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self.assertEqual(self.vocab.lookup([[[[["a", "b"]]]]]), ((((("a", "b"),),),),))
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def test_lookup_None(self):
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with self.assertRaises(TypeError):
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self.vocab.lookup(None)
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with self.assertRaises(TypeError):
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list(self.vocab.lookup([None, None]))
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def test_lookup_int(self):
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with self.assertRaises(TypeError):
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self.vocab.lookup(1)
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with self.assertRaises(TypeError):
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list(self.vocab.lookup([1, 2]))
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def test_lookup_empty_str(self):
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self.assertEqual(self.vocab.lookup(""), "<UNK>")
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def test_eqality(self):
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v1 = Vocabulary(["a", "b", "c"], unk_cutoff=1)
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v2 = Vocabulary(["a", "b", "c"], unk_cutoff=1)
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v3 = Vocabulary(["a", "b", "c"], unk_cutoff=1, unk_label="blah")
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v4 = Vocabulary(["a", "b"], unk_cutoff=1)
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self.assertEqual(v1, v2)
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self.assertNotEqual(v1, v3)
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self.assertNotEqual(v1, v4)
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def test_str(self):
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self.assertEqual(
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str(self.vocab), "<Vocabulary with cutoff=2 unk_label='<UNK>' and 5 items>"
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)
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def test_creation_with_counter(self):
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self.assertEqual(
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self.vocab,
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Vocabulary(
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Counter(
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["z", "a", "b", "c", "f", "d", "e", "g", "a", "d", "b", "e", "w"]
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),
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unk_cutoff=2,
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),
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)
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@unittest.skip(
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reason="Test is known to be flaky as it compares (runtime) performance."
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)
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def test_len_is_constant(self):
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# Given an obviously small and an obviously large vocabulary.
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small_vocab = Vocabulary("abcde")
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from nltk.corpus.europarl_raw import english
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large_vocab = Vocabulary(english.words())
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# If we time calling `len` on them.
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small_vocab_len_time = timeit("len(small_vocab)", globals=locals())
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large_vocab_len_time = timeit("len(large_vocab)", globals=locals())
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# The timing should be the same order of magnitude.
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self.assertAlmostEqual(small_vocab_len_time, large_vocab_len_time, places=1)
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