# -*- coding: utf-8 -*-
"""
Unit tests for nltk.metrics.aline
"""

from __future__ import unicode_literals

import unittest

from nltk.metrics import aline


class TestAline(unittest.TestCase):
    """
    Test Aline algorithm for aligning phonetic sequences
    """

    def test_aline(self):
        result = aline.align('θin', 'tenwis')
        expected = [
            [('θ', 't'), ('i', 'e'), ('n', 'n'), ('-', 'w'), ('-', 'i'), ('-', 's')]
        ]

        self.assertEqual(result, expected)

        result = aline.align('jo', 'ʒə')
        expected = [[('j', 'ʒ'), ('o', 'ə')]]

        self.assertEqual(result, expected)

        result = aline.align('pematesiweni', 'pematesewen')
        expected = [
            [
                ('p', 'p'),
                ('e', 'e'),
                ('m', 'm'),
                ('a', 'a'),
                ('t', 't'),
                ('e', 'e'),
                ('s', 's'),
                ('i', 'e'),
                ('w', 'w'),
                ('e', 'e'),
                ('n', 'n'),
                ('i', '-'),
            ]
        ]

        self.assertEqual(result, expected)

        result = aline.align('tuwθ', 'dentis')
        expected = [
            [
                ('t', 'd'),
                ('u', 'e'),
                ('w', '-'),
                ('-', 'n'),
                ('-', 't'),
                ('-', 'i'),
                ('θ', 's'),
            ]
        ]

        self.assertEqual(result, expected)

    def test_aline_delta(self):
        """
        Test aline for computing the difference between two segments
        """
        result = aline.delta('p', 'q')
        expected = 20.0

        self.assertEqual(result, expected)

        result = aline.delta('a', 'A')
        expected = 0.0

        self.assertEqual(result, expected)