require "test/unit"
require "levenshtein"

class TestLevenshtein < Test::Unit::TestCase
  def test_erik_veenstra
    assert_equal(7, Levenshtein.distance("erik", "veenstra"))
    assert_equal(7, Levenshtein.distance("veenstra", "erik"))

    assert_in_delta(0.875, Levenshtein.normalized_distance("erik", "veenstra"), 0.01)
    assert_in_delta(0.875, Levenshtein.normalized_distance("veenstra", "erik"), 0.01)
  end

  def test_empty_string
    assert_equal(0, Levenshtein.distance("", ""))
    assert_equal(3, Levenshtein.distance("", "foo"))
    assert_equal(3, Levenshtein.distance("foo", ""))

    assert_in_delta(0.0, Levenshtein.normalized_distance("", ""), 0.01)
    assert_in_delta(1.0, Levenshtein.normalized_distance("", "foo"), 0.01)
    assert_in_delta(1.0, Levenshtein.normalized_distance("foo", ""), 0.01)
  end

  def test_same_string
    assert_equal(0, Levenshtein.distance("", ""))
    assert_equal(0, Levenshtein.distance("foo", "foo"))

    assert_in_delta(0.0, Levenshtein.normalized_distance("", ""), 0.01)
    assert_in_delta(0.0, Levenshtein.normalized_distance("foo", "foo"), 0.01)
  end

  def test_threshold
    assert_equal(3, Levenshtein.distance("foo", "foobar"))
    assert_equal(nil, Levenshtein.distance("foo", "foobar", 2))

    assert_in_delta(0.5, Levenshtein.normalized_distance("foo", "foobar"), 0.01)
    assert_equal(nil, Levenshtein.normalized_distance("foo", "foobar", 0.30))
  end

  def test_same_head_and_or_tail
    assert_equal(3, Levenshtein.distance("ab123cd", "abxyzcd"))
    assert_equal(3, Levenshtein.distance("ab123", "abxyz"))
    assert_equal(3, Levenshtein.distance("123cd", "xyzcd"))

    assert_in_delta(0.42, Levenshtein.normalized_distance("ab123cd", "abxyzcd"), 0.01)
    assert_in_delta(0.6, Levenshtein.normalized_distance("ab123", "abxyz"), 0.01)
    assert_in_delta(0.6, Levenshtein.normalized_distance("123cd", "xyzcd"), 0.01)
  end
end

class TestLevenshteinPart2Slow < Test::Unit::TestCase
  def test_erik_veenstra
    assert_equal(7, Levenshtein.distance_part2_slow("erik", "veenstra", nil))
  end

  def test_empty_string
    assert_equal(0, Levenshtein.distance_part2_slow("", "", nil))
    assert_equal(3, Levenshtein.distance_part2_slow("", "foo", nil))
  end

  def test_same_string
    assert_equal(0, Levenshtein.distance_part2_slow("", "", nil))
    assert_equal(0, Levenshtein.distance_part2_slow("foo", "foo", nil))
  end

  def test_threshold
    assert_equal(3, Levenshtein.distance_part2_slow("foo", "foobar", nil))
    assert_equal(nil, Levenshtein.distance_part2_slow("foo", "foobar", 2))
  end
end

class TestLevenshteinPart2Fast < Test::Unit::TestCase
  def test_erik_veenstra
    assert_equal(7, Levenshtein.distance_part2_fast("erik", "veenstra", nil))
  end

  def test_empty_string
    assert_equal(0, Levenshtein.distance_part2_fast("", "", nil))
    assert_equal(3, Levenshtein.distance_part2_fast("", "foo", nil))
  end

  def test_same_string
    assert_equal(0, Levenshtein.distance_part2_fast("", "", nil))
    assert_equal(0, Levenshtein.distance_part2_fast("foo", "foo", nil))
  end

  def test_threshold
    assert_equal(3, Levenshtein.distance_part2_fast("foo", "foobar", nil))
    assert_equal(nil, Levenshtein.distance_part2_fast("foo", "foobar", 2))
  end
end