luau/tests/StringUtils.test.cpp
Arseny Kapoulkine d01addc625 Sync to upstream/release/501 (#20)
Co-authored-by: Rodactor <rodactor@roblox.com>
2021-11-01 14:52:34 -07:00

109 lines
3.4 KiB
C++

// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
#include "Luau/StringUtils.h"
#include "doctest.h"
#include <iostream>
namespace
{
using LevenshteinMatrix = std::vector<std::vector<size_t>>;
std::string format(std::string_view a, std::string_view b, size_t expected, size_t actual)
{
return "Distance of '" + std::string(a) + "' and '" + std::string(b) + "': expected " + std::to_string(expected) + ", got " +
std::to_string(actual);
}
// Each call to this function is not one test, but instead actually runs tests (A.size() * B.size()) + 2 times.
void compareLevenshtein(LevenshteinMatrix distances, std::string_view a, std::string_view b)
{
for (size_t x = 0; x <= a.size(); ++x)
{
for (size_t y = 0; y <= b.size(); ++y)
{
std::string_view currentA = a.substr(0, x);
std::string_view currentB = b.substr(0, y);
size_t actual = Luau::editDistance(currentA, currentB);
size_t expected = distances[x][y];
CHECK_MESSAGE(actual == expected, format(currentA, currentB, expected, actual));
}
}
}
} // namespace
TEST_SUITE_BEGIN("StringUtilsTest");
#if 0
// This unit test is only used to measure how performant the current levenshtein distance algorithm is.
// It is entirely ok to submit this, but keep #if 0.
TEST_CASE("BenchmarkLevenshteinDistance")
{
// For reference: running this benchmark on a Macbook Pro 16 takes ~250ms.
int count = 1'000'000;
// specifically chosen because they:
// - are real words,
// - have common prefix and suffix, and
// - are sufficiently long enough to stress test with
std::string_view a("Intercalate");
std::string_view b("Interchangeable");
auto start = std::chrono::steady_clock::now();
for (int i = 0; i < count; ++i)
Luau::editDistance(a, b);
auto end = std::chrono::steady_clock::now();
auto time = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
std::cout << "Running levenshtein distance " << count << " times took " << time.count() << "ms" << std::endl;
}
#endif
TEST_CASE("LevenshteinDistanceKittenSitting")
{
LevenshteinMatrix distances{
{0, 1, 2, 3, 4, 5, 6, 7}, // S I T T I N G
{1, 1, 2, 3, 4, 5, 6, 7}, // K
{2, 2, 1, 2, 3, 4, 5, 6}, // I
{3, 3, 2, 1, 2, 3, 4, 5}, // T
{4, 4, 3, 2, 1, 2, 3, 4}, // T
{5, 5, 4, 3, 2, 2, 3, 4}, // E
{6, 6, 5, 4, 3, 3, 2, 3}, // N
};
compareLevenshtein(distances, "kitten", "sitting");
}
TEST_CASE("LevenshteinDistanceSaturdaySunday")
{
LevenshteinMatrix distances{
{0, 1, 2, 3, 4, 5, 6}, // S U N D A Y
{1, 0, 1, 2, 3, 4, 5}, // S
{2, 1, 1, 2, 3, 3, 4}, // A
{3, 2, 2, 2, 3, 4, 4}, // T
{4, 3, 2, 3, 3, 4, 5}, // U
{5, 4, 3, 3, 4, 4, 5}, // R
{6, 5, 4, 4, 3, 4, 5}, // D
{7, 6, 5, 5, 4, 3, 4}, // A
{8, 7, 6, 6, 5, 4, 3}, // Y
};
compareLevenshtein(distances, "saturday", "sunday");
}
TEST_CASE("EditDistanceIsAgnosticOfArgumentOrdering")
{
CHECK_EQ(Luau::editDistance("blox", "block"), Luau::editDistance("block", "blox"));
}
TEST_CASE("AreWeUsingDistanceWithAdjacentTranspositionsAndNotOptimalStringAlignment")
{
size_t distance = Luau::editDistance("CA", "ABC");
CHECK_EQ(distance, 2);
}
TEST_SUITE_END();