Introduce IsGraphemeBreak function.

third_party/WebKit/Source/core/editing/state_machines/StateMachineUtilTest.cpp

Index: third_party/WebKit/Source/core/editing/state_machines/StateMachineUtilTest.cpp
diff --git a/third_party/WebKit/Source/core/editing/state_machines/StateMachineUtilTest.cpp b/third_party/WebKit/Source/core/editing/state_machines/StateMachineUtilTest.cpp
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index 0000000000000000000000000000000000000000..d5ab01f863bfc88ca953165c6f1d4008acc2818c
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+++ b/third_party/WebKit/Source/core/editing/state_machines/StateMachineUtilTest.cpp
@@ -0,0 +1,165 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/editing/state_machines/StateMachineUtil.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "wtf/text/CharacterNames.h"
+#include "wtf/text/Unicode.h"
+
+namespace blink {
+
+TEST(StateMachineUtilTest, IsGraphmeBreak_LineBreak)
+{
+    // U+000AD (SOFT HYPHEN) has Control grapheme property.
+    const UChar32 kControl = WTF::Unicode::softHyphenCharacter;
+
+    // Grapheme Cluster Boundary Rule GB3: CR x LF
+    EXPECT_FALSE(isGraphemeBreak('\r', '\n'));
+    EXPECT_TRUE(isGraphemeBreak('\n', '\r'));
+
+    // Grapheme Cluster Boundary Rule GB4: (Control | CR | LF) ÷
+    EXPECT_TRUE(isGraphemeBreak('\r', 'a'));
+    EXPECT_TRUE(isGraphemeBreak('\n', 'a'));
+    EXPECT_TRUE(isGraphemeBreak(kControl, 'a'));
+
+    // Grapheme Cluster Boundary Rule GB5: ÷ (Control | CR | LF)
+    EXPECT_TRUE(isGraphemeBreak('a', '\r'));
+    EXPECT_TRUE(isGraphemeBreak('a', '\n'));
+    EXPECT_TRUE(isGraphemeBreak('a', kControl));
+}
+
+TEST(StateMachineUtilTest, IsGraphmeBreak_Hangul)
+{
+    // U+1100 (HANGUL CHOSEONG KIYEOK) has L grapheme property.
+    const UChar32 kL = 0x1100;
+    // U+1160 (HANGUL JUNGSEONG FILLER) has V grapheme property.
+    const UChar32 kV = 0x1160;
+    // U+AC00 (HANGUL SYLLABLE GA) has LV grapheme property.
+    const UChar32 kLV = 0xAC00;
+    // U+AC01 (HANGUL SYLLABLE GAG) has LVT grapheme property.
+    const UChar32 kLVT = 0xAC01;
+    // U+11A8 (HANGUL JONGSEONG KIYEOK) has T grapheme property.
+    const UChar32 kT = 0x11A8;
+
+    // Grapheme Cluster Boundary Rule GB6: L x (L | V | LV | LVT)
+    EXPECT_FALSE(isGraphemeBreak(kL, kL));
+    EXPECT_FALSE(isGraphemeBreak(kL, kV));
+    EXPECT_FALSE(isGraphemeBreak(kL, kLV));
+    EXPECT_FALSE(isGraphemeBreak(kL, kLVT));
+    EXPECT_TRUE(isGraphemeBreak(kL, kT));
+
+    // Grapheme Cluster Boundary Rule GB7: (LV | V) x (V | T)
+    EXPECT_TRUE(isGraphemeBreak(kV, kL));
+    EXPECT_FALSE(isGraphemeBreak(kV, kV));
+    EXPECT_TRUE(isGraphemeBreak(kV, kLV));
+    EXPECT_TRUE(isGraphemeBreak(kV, kLVT));
+    EXPECT_FALSE(isGraphemeBreak(kV, kT));
+
+    // Grapheme Cluster Boundary Rule GB7: (LV | V) x (V | T)
+    EXPECT_TRUE(isGraphemeBreak(kLV, kL));
+    EXPECT_FALSE(isGraphemeBreak(kLV, kV));
+    EXPECT_TRUE(isGraphemeBreak(kLV, kLV));
+    EXPECT_TRUE(isGraphemeBreak(kLV, kLVT));
+    EXPECT_FALSE(isGraphemeBreak(kLV, kT));
+
+    // Grapheme Cluster Boundary Rule GB8: (LVT | T) x T
+    EXPECT_TRUE(isGraphemeBreak(kLVT, kL));
+    EXPECT_TRUE(isGraphemeBreak(kLVT, kV));
+    EXPECT_TRUE(isGraphemeBreak(kLVT, kLV));
+    EXPECT_TRUE(isGraphemeBreak(kLVT, kLVT));
+    EXPECT_FALSE(isGraphemeBreak(kLVT, kT));
+
+    // Grapheme Cluster Boundary Rule GB8: (LVT | T) x T
+    EXPECT_TRUE(isGraphemeBreak(kT, kL));
+    EXPECT_TRUE(isGraphemeBreak(kT, kV));
+    EXPECT_TRUE(isGraphemeBreak(kT, kLV));
+    EXPECT_TRUE(isGraphemeBreak(kT, kLVT));
+    EXPECT_FALSE(isGraphemeBreak(kT, kT));
+}
+
+TEST(StateMachineUtilTest, IsGraphmeBreak_Extend_or_ZWJ)
+{
+    // U+0300 (COMBINING GRAVE ACCENT) has Extend grapheme property.
+    const UChar32 kExtend = 0x0300;
+    // Grapheme Cluster Boundary Rule GB9: x (Extend | ZWJ)
+    EXPECT_FALSE(isGraphemeBreak('a', kExtend));
+    EXPECT_FALSE(isGraphemeBreak('a', WTF::Unicode::zeroWidthJoinerCharacter));
+    EXPECT_FALSE(isGraphemeBreak(kExtend, kExtend));
+    EXPECT_FALSE(isGraphemeBreak(WTF::Unicode::zeroWidthJoinerCharacter,
+        WTF::Unicode::zeroWidthJoinerCharacter));
+    EXPECT_FALSE(isGraphemeBreak(kExtend,
+        WTF::Unicode::zeroWidthJoinerCharacter));
+    EXPECT_FALSE(isGraphemeBreak(WTF::Unicode::zeroWidthJoinerCharacter,
+        kExtend));
+}
+
+TEST(StateMachineUtilTest, IsGraphmeBreak_SpacingMark)
+{
+    // U+0903 (DEVANAGARI SIGN VISARGA) has SpacingMark grapheme property.
+    const UChar32 kSpacingMark = 0x0903;
+
+    // Grapheme Cluster Boundary Rule GB9a: x SpacingMark.
+    EXPECT_FALSE(isGraphemeBreak('a', kSpacingMark));
+}
+
+// TODO(nona): Introduce tests for GB9b rule once ICU grabs Unicod 9.0.
+// There is no character having Prepend grapheme property in Unicode 8.0.
+
+TEST(StateMachineUtilTest, IsGraphmeBreak_EmojiModifier)
+{
+    // U+261D (WHITE UP POINTING INDEX) has E_Base grapheme property.
+    const UChar32 kEBase = 0x261D;
+    // U+1F466 (BOY) has E_Base_GAZ grapheme property.
+    const UChar32 kEBaseGAZ = 0x1F466;
+    // U+1F3FB (EMOJI MODIFIER FITZPATRICK TYPE-1-2) has E_Modifier grapheme
+    // property.
+    const UChar32 kEModifier = 0x1F3FB;
+
+    // Grapheme Cluster Boundary Rule GB10: (E_Base, E_Base_GAZ) x E_Modifier
+    EXPECT_FALSE(isGraphemeBreak(kEBase, kEModifier));
+    EXPECT_FALSE(isGraphemeBreak(kEBaseGAZ, kEModifier));
+    EXPECT_FALSE(isGraphemeBreak(kEBase, kEModifier));
+
+    EXPECT_TRUE(isGraphemeBreak(kEBase, kEBase));
+    EXPECT_TRUE(isGraphemeBreak(kEBaseGAZ, kEBase));
+    EXPECT_TRUE(isGraphemeBreak(kEBase, kEBaseGAZ));
+    EXPECT_TRUE(isGraphemeBreak(kEBaseGAZ, kEBaseGAZ));
+    EXPECT_TRUE(isGraphemeBreak(kEModifier, kEModifier));
+}
+
+TEST(StateMachineUtilTest, IsGraphmeBreak_ZWJSequecne)
+{
+    // U+2764 (HEAVY BLACK HEART) has Glue_After_Zwj grapheme property.
+    const UChar32 kGlueAfterZwj = 0x2764;
+    // U+1F466 (BOY) has E_Base_GAZ grapheme property.
+    const UChar32 kEBaseGAZ = 0x1F466;
+
+    // Grapheme Cluster Boundary Rule GB11: ZWJ x (Glue_After_Zwj | EBG)
+    EXPECT_FALSE(isGraphemeBreak(WTF::Unicode::zeroWidthJoinerCharacter,
+        kGlueAfterZwj));
+    EXPECT_FALSE(isGraphemeBreak(WTF::Unicode::zeroWidthJoinerCharacter,
+        kEBaseGAZ));
+
+    EXPECT_TRUE(isGraphemeBreak(kGlueAfterZwj, kEBaseGAZ));
+    EXPECT_TRUE(isGraphemeBreak(kGlueAfterZwj, kGlueAfterZwj));
+    EXPECT_TRUE(isGraphemeBreak(kEBaseGAZ, kGlueAfterZwj));
+}
+
+TEST(StateMachineUtilTest, IsGraphmeBreak_IndicSyllabicCategoryVirama)
+{
+    // U+094D (DEVANAGARI SIGN VIRAMA) has Indic_Syllabic_Category=Virama
+    // property.
+    const UChar32 kVirama = 0x094D;
+
+    // U+0915 (DEVANAGARI LETTER KA). Should not break after kVirama and before
+    // this character.
+    const UChar32 kDevangariKa = 0x0915;
+
+    // Do not break after character having Indic_Syllabic_Category=Virama
+    // property if following character has General_Category=C(Other) property.
+    EXPECT_FALSE(isGraphemeBreak(kVirama, kDevangariKa));
+}
+
+} // namespace blink