LibUnicode: Add a unit test for Unicode grapheme and word segmentation

These include tests for previously broken boundary conditions.

2 files changed, 102 insertions, 0 deletions

diff --git a/Tests/LibUnicode/CMakeLists.txt b/Tests/LibUnicode/CMakeLists.txt
index 0b43421ce2..06e904c21a 100644
--- a/Tests/LibUnicode/CMakeLists.txt
+++ b/Tests/LibUnicode/CMakeLists.txt
@@ -1,5 +1,6 @@
 set(TEST_SOURCES
     TestEmoji.cpp
+    TestSegmentation.cpp
     TestUnicodeCharacterTypes.cpp
     TestUnicodeNormalization.cpp
 )
diff --git a/Tests/LibUnicode/TestSegmentation.cpp b/Tests/LibUnicode/TestSegmentation.cpp
new file mode 100644
index 0000000000..1159ae875b
--- /dev/null
+++ b/Tests/LibUnicode/TestSegmentation.cpp
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Array.h>
+#include <AK/StringView.h>
+#include <AK/Utf8View.h>
+#include <AK/Vector.h>
+#include <LibTest/TestCase.h>
+#include <LibUnicode/Segmentation.h>
+
+template<size_t N>
+static void test_grapheme_segmentation(StringView string, size_t const (&expected_boundaries)[N])
+{
+    Vector<size_t> boundaries;
+    Utf8View view { string };
+
+    Unicode::for_each_grapheme_segmentation_boundary(view, [&](auto boundary) {
+        boundaries.append(boundary);
+        return IterationDecision::Continue;
+    });
+
+    EXPECT_EQ(boundaries, ReadonlySpan<size_t> { expected_boundaries });
+}
+
+TEST_CASE(grapheme_segmentation)
+{
+    Unicode::for_each_grapheme_segmentation_boundary(Utf8View {}, [&](auto) {
+        VERIFY_NOT_REACHED();
+        return IterationDecision::Break;
+    });
+
+    test_grapheme_segmentation("a"sv, { 0u, 1u });
+    test_grapheme_segmentation("ab"sv, { 0u, 1u, 2u });
+    test_grapheme_segmentation("abc"sv, { 0u, 1u, 2u, 3u });
+
+    test_grapheme_segmentation("a\nb"sv, { 0u, 1u, 2u, 3u });
+    test_grapheme_segmentation("a\n\rb"sv, { 0u, 1u, 2u, 3u, 4u });
+    test_grapheme_segmentation("a\r\nb"sv, { 0u, 1u, 3u, 4u });
+
+    test_grapheme_segmentation("aᄀb"sv, { 0u, 1u, 4u, 5u });
+    test_grapheme_segmentation("aᄀᄀb"sv, { 0u, 1u, 7u, 8u });
+    test_grapheme_segmentation("aᄀᆢb"sv, { 0u, 1u, 7u, 8u });
+    test_grapheme_segmentation("aᄀ가b"sv, { 0u, 1u, 7u, 8u });
+    test_grapheme_segmentation("aᄀ각b"sv, { 0u, 1u, 7u, 8u });
+
+    test_grapheme_segmentation("a😀b"sv, { 0u, 1u, 5u, 6u });
+    test_grapheme_segmentation("a👨‍👩‍👧‍👦b"sv, { 0u, 1u, 26u, 27u });
+    test_grapheme_segmentation("a👩🏼‍❤️‍👨🏻b"sv, { 0u, 1u, 29u, 30u });
+}
+
+template<size_t N>
+static void test_word_segmentation(StringView string, size_t const (&expected_boundaries)[N])
+{
+    Vector<size_t> boundaries;
+    Utf8View view { string };
+
+    Unicode::for_each_word_segmentation_boundary(view, [&](auto boundary) {
+        boundaries.append(boundary);
+        return IterationDecision::Continue;
+    });
+
+    EXPECT_EQ(boundaries, ReadonlySpan<size_t> { expected_boundaries });
+}
+
+TEST_CASE(word_segmentation)
+{
+    Unicode::for_each_word_segmentation_boundary(Utf8View {}, [&](auto) {
+        VERIFY_NOT_REACHED();
+        return IterationDecision::Break;
+    });
+
+    test_word_segmentation("a"sv, { 0u, 1u });
+    test_word_segmentation("ab"sv, { 0u, 2u });
+    test_word_segmentation("abc"sv, { 0u, 3u });
+
+    test_word_segmentation("ab cd"sv, { 0u, 2u, 3u, 5u });
+    test_word_segmentation("ab  cd"sv, { 0u, 2u, 4u, 6u });
+    test_word_segmentation("ab\tcd"sv, { 0u, 2u, 3u, 5u });
+    test_word_segmentation("ab\ncd"sv, { 0u, 2u, 3u, 5u });
+    test_word_segmentation("ab\n\rcd"sv, { 0u, 2u, 3u, 4u, 6u });
+    test_word_segmentation("ab\r\ncd"sv, { 0u, 2u, 4u, 6u });
+
+    test_word_segmentation("a😀b"sv, { 0u, 1u, 5u, 6u });
+    test_word_segmentation("a👨‍👩‍👧‍👦b"sv, { 0u, 1u, 26u, 27u });
+    test_word_segmentation("a👩🏼‍❤️‍👨🏻b"sv, { 0u, 1u, 29u, 30u });
+
+    test_word_segmentation("ab 12 cd"sv, { 0u, 2u, 3u, 5u, 6u, 8u });
+    test_word_segmentation("ab 1.2 cd"sv, { 0u, 2u, 3u, 6u, 7u, 9u });
+    test_word_segmentation("ab 12.34 cd"sv, { 0u, 2u, 3u, 8u, 9u, 11u });
+    test_word_segmentation("ab example.com cd"sv, { 0u, 2u, 3u, 14u, 15u, 17u });
+
+    test_word_segmentation("ab can't cd"sv, { 0u, 2u, 3u, 8u, 9u, 11u });
+    test_word_segmentation("ab \"can't\" cd"sv, { 0u, 2u, 3u, 4u, 9u, 10u, 11u, 13u });
+
+    test_word_segmentation(
+        "The quick (“brown”) fox can’t jump 32.3 feet, right?"sv,
+        { 0u, 3u, 4u, 9u, 10u, 11u, 14u, 19u, 22u, 23u, 24u, 27u, 28u, 35u, 36u, 40u, 41u, 45u, 46u, 50u, 51u, 52u, 57u, 58u });
+}