/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "minikin/Layout.h"

#include <gtest/gtest.h>

#include "minikin/FontCollection.h"
#include "minikin/LayoutPieces.h"

#include "FontTestUtils.h"
#include "UnicodeUtils.h"

namespace minikin {

const float UNTOUCHED_MARKER = 1e+38;

static void expectAdvances(std::vector<float> expected, float* advances, size_t length) {
    EXPECT_LE(expected.size(), length);
    for (size_t i = 0; i < expected.size(); ++i) {
        EXPECT_EQ(expected[i], advances[i])
                << i << "th element is different. Expected: " << expected[i]
                << ", Actual: " << advances[i];
    }
    EXPECT_EQ(UNTOUCHED_MARKER, advances[expected.size()]);
}

static void resetAdvances(float* advances, size_t length) {
    for (size_t i = 0; i < length; ++i) {
        advances[i] = UNTOUCHED_MARKER;
    }
}

static Layout doLayout(const std::string& text, const MinikinPaint& paint) {
    Layout layout;
    auto utf16 = utf8ToUtf16(text);
    Range range(0, utf16.size());
    layout.doLayout(utf16, range, Bidi::FORCE_LTR, paint, StartHyphenEdit::NO_EDIT,
                    EndHyphenEdit::NO_EDIT);
    return layout;
}

static Layout doLayoutWithPrecomputedPieces(const std::string& text, const MinikinPaint& paint,
                                            const LayoutPieces& pieces) {
    Layout layout;
    auto utf16 = utf8ToUtf16(text);
    Range range(0, utf16.size());
    layout.doLayoutWithPrecomputedPieces(utf16, range, Bidi::FORCE_LTR, paint,
                                         StartHyphenEdit::NO_EDIT, EndHyphenEdit::NO_EDIT, pieces);
    return layout;
}

class LayoutTest : public testing::Test {
protected:
    LayoutTest() : mCollection(nullptr) {}

    virtual ~LayoutTest() {}

    virtual void SetUp() override { mCollection = buildFontCollection("Ascii.ttf"); }

    virtual void TearDown() override {}

    std::shared_ptr<FontCollection> mCollection;
};

TEST_F(LayoutTest, doLayoutTest) {
    MinikinPaint paint(mCollection);
    paint.size = 10.0f;  // make 1em = 10px
    MinikinRect rect;
    const size_t kMaxAdvanceLength = 32;
    float advances[kMaxAdvanceLength];
    std::vector<float> expectedValues;

    Layout layout;
    std::vector<uint16_t> text;

    // The mock implementation returns 10.0f advance and 0,0-10x10 bounds for all glyph.
    {
        SCOPED_TRACE("one word");
        text = utf8ToUtf16("oneword");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(70.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(70.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
    {
        SCOPED_TRACE("two words");
        text = utf8ToUtf16("two words");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(90.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(90.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
    {
        SCOPED_TRACE("three words");
        text = utf8ToUtf16("three words test");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(160.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(160.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
    {
        SCOPED_TRACE("two spaces");
        text = utf8ToUtf16("two  spaces");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(110.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(110.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
}

TEST_F(LayoutTest, doLayoutTest_wordSpacing) {
    MinikinPaint paint(mCollection);
    paint.size = 10.0f;  // make 1em = 10px
    MinikinRect rect;
    const size_t kMaxAdvanceLength = 32;
    float advances[kMaxAdvanceLength];
    std::vector<float> expectedValues;
    std::vector<uint16_t> text;

    Layout layout;

    paint.wordSpacing = 5.0f;

    // The mock implementation returns 10.0f advance and 0,0-10x10 bounds for all glyph.
    {
        SCOPED_TRACE("one word");
        text = utf8ToUtf16("oneword");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(70.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(70.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
    {
        SCOPED_TRACE("two words");
        text = utf8ToUtf16("two words");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(95.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(95.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        EXPECT_EQ(UNTOUCHED_MARKER, advances[text.size()]);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectedValues[3] = 15.0f;
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
    {
        SCOPED_TRACE("three words test");
        text = utf8ToUtf16("three words test");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(170.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(170.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectedValues[5] = 15.0f;
        expectedValues[11] = 15.0f;
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
    {
        SCOPED_TRACE("two spaces");
        text = utf8ToUtf16("two  spaces");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(120.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(120.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectedValues[3] = 15.0f;
        expectedValues[4] = 15.0f;
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
}

TEST_F(LayoutTest, doLayoutTest_negativeWordSpacing) {
    MinikinPaint paint(mCollection);
    paint.size = 10.0f;  // make 1em = 10px
    MinikinRect rect;
    const size_t kMaxAdvanceLength = 32;
    float advances[kMaxAdvanceLength];
    std::vector<float> expectedValues;

    Layout layout;
    std::vector<uint16_t> text;

    // Negative word spacing also should work.
    paint.wordSpacing = -5.0f;

    {
        SCOPED_TRACE("one word");
        text = utf8ToUtf16("oneword");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(70.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(70.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
    {
        SCOPED_TRACE("two words");
        text = utf8ToUtf16("two words");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(85.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(85.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectedValues[3] = 5.0f;
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
    {
        SCOPED_TRACE("three words");
        text = utf8ToUtf16("three word test");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(140.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(140.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectedValues[5] = 5.0f;
        expectedValues[10] = 5.0f;
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
    {
        SCOPED_TRACE("two spaces");
        text = utf8ToUtf16("two  spaces");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(100.0f, layout.getAdvance());
        layout.getBounds(&rect);
        EXPECT_EQ(0.0f, rect.mLeft);
        EXPECT_EQ(10.0f, rect.mTop);
        EXPECT_EQ(100.0f, rect.mRight);
        EXPECT_EQ(0.0f, rect.mBottom);
        resetAdvances(advances, kMaxAdvanceLength);
        layout.getAdvances(advances);
        expectedValues.resize(text.size());
        for (size_t i = 0; i < expectedValues.size(); ++i) {
            expectedValues[i] = 10.0f;
        }
        expectedValues[3] = 5.0f;
        expectedValues[4] = 5.0f;
        expectAdvances(expectedValues, advances, kMaxAdvanceLength);
    }
}

// Test that a forced-RTL layout correctly mirros a forced-LTR layout.
TEST_F(LayoutTest, doLayoutTest_rtlTest) {
    MinikinPaint paint(mCollection);

    std::vector<uint16_t> text = parseUnicodeString("'a' 'b' U+3042 U+3043 'c' 'd'");
    Range range(0, text.size());

    Layout ltrLayout;
    ltrLayout.doLayout(text, range, Bidi::FORCE_LTR, paint, StartHyphenEdit::NO_EDIT,
                       EndHyphenEdit::NO_EDIT);

    Layout rtlLayout;
    rtlLayout.doLayout(text, range, Bidi::FORCE_RTL, paint, StartHyphenEdit::NO_EDIT,
                       EndHyphenEdit::NO_EDIT);

    ASSERT_EQ(ltrLayout.nGlyphs(), rtlLayout.nGlyphs());
    ASSERT_EQ(6u, ltrLayout.nGlyphs());

    size_t nGlyphs = ltrLayout.nGlyphs();
    for (size_t i = 0; i < nGlyphs; ++i) {
        EXPECT_EQ(ltrLayout.getFont(i), rtlLayout.getFont(nGlyphs - i - 1));
        EXPECT_EQ(ltrLayout.getGlyphId(i), rtlLayout.getGlyphId(nGlyphs - i - 1));
    }
}

// Test that single-run RTL layouts of LTR-only text is laid out identical to an LTR layout.
TEST_F(LayoutTest, singleRunBidiTest) {
    MinikinPaint paint(mCollection);

    std::vector<uint16_t> text = parseUnicodeString("'1' '2' '3'");
    Range range(0, text.size());

    Layout ltrLayout;
    ltrLayout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                       EndHyphenEdit::NO_EDIT);

    Layout rtlLayout;
    rtlLayout.doLayout(text, range, Bidi::RTL, paint, StartHyphenEdit::NO_EDIT,
                       EndHyphenEdit::NO_EDIT);

    Layout defaultRtlLayout;
    defaultRtlLayout.doLayout(text, range, Bidi::DEFAULT_RTL, paint, StartHyphenEdit::NO_EDIT,
                              EndHyphenEdit::NO_EDIT);

    const size_t nGlyphs = ltrLayout.nGlyphs();
    ASSERT_EQ(3u, nGlyphs);

    ASSERT_EQ(nGlyphs, rtlLayout.nGlyphs());
    ASSERT_EQ(nGlyphs, defaultRtlLayout.nGlyphs());

    for (size_t i = 0; i < nGlyphs; ++i) {
        EXPECT_EQ(ltrLayout.getFont(i), rtlLayout.getFont(i));
        EXPECT_EQ(ltrLayout.getGlyphId(i), rtlLayout.getGlyphId(i));
        EXPECT_EQ(ltrLayout.getFont(i), defaultRtlLayout.getFont(i));
        EXPECT_EQ(ltrLayout.getGlyphId(i), defaultRtlLayout.getGlyphId(i));
    }
}

TEST_F(LayoutTest, hyphenationTest) {
    MinikinPaint paint(mCollection);
    paint.size = 10.0f;  // make 1em = 10px
    Layout layout;
    std::vector<uint16_t> text;

    // The mock implementation returns 10.0f advance for all glyphs.
    {
        SCOPED_TRACE("one word with no hyphen edit");
        text = utf8ToUtf16("oneword");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(70.0f, layout.getAdvance());
    }
    {
        SCOPED_TRACE("one word with hyphen insertion at the end");
        text = utf8ToUtf16("oneword");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::INSERT_HYPHEN);
        EXPECT_EQ(80.0f, layout.getAdvance());
    }
    {
        SCOPED_TRACE("one word with hyphen replacement at the end");
        text = utf8ToUtf16("oneword");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                        EndHyphenEdit::REPLACE_WITH_HYPHEN);
        EXPECT_EQ(70.0f, layout.getAdvance());
    }
    {
        SCOPED_TRACE("one word with hyphen insertion at the start");
        text = utf8ToUtf16("oneword");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::INSERT_HYPHEN,
                        EndHyphenEdit::NO_EDIT);
        EXPECT_EQ(80.0f, layout.getAdvance());
    }
    {
        SCOPED_TRACE("one word with hyphen insertion at the both ends");
        text = utf8ToUtf16("oneword");
        Range range(0, text.size());
        layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::INSERT_HYPHEN,
                        EndHyphenEdit::INSERT_HYPHEN);
        EXPECT_EQ(90.0f, layout.getAdvance());
    }
}

TEST_F(LayoutTest, verticalExtentTest) {
    MinikinPaint paint(mCollection);

    std::vector<uint16_t> text = utf8ToUtf16("ab");
    Range range(0, text.size());

    Layout layout;
    layout.doLayout(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                    EndHyphenEdit::NO_EDIT);
    MinikinExtent extents[text.size()];
    layout.getExtents(extents);
    for (size_t i = 0; i < text.size(); i++) {
        EXPECT_EQ(-10.0f, extents[i].ascent);
        EXPECT_EQ(20.0f, extents[i].descent);
        EXPECT_EQ(0.0f, extents[i].line_gap);
    }
}

TEST_F(LayoutTest, measuredTextTest) {
    // The test font has following coverage and width.
    // U+0020: 10em
    // U+002E (.): 10em
    // U+0043 (C): 100em
    // U+0049 (I): 1em
    // U+004C (L): 50em
    // U+0056 (V): 5em
    // U+0058 (X): 10em
    // U+005F (_): 0em
    // U+FFFD (invalid surrogate will be replaced to this): 7em
    // U+10331 (\uD800\uDF31): 10em
    auto fc = buildFontCollection("LayoutTestFont.ttf");
    {
        MinikinPaint paint(fc);
        std::vector<uint16_t> text = utf8ToUtf16("I");
        std::vector<float> advances(text.size());
        Range range(0, text.size());
        EXPECT_EQ(1.0f,
                  Layout::measureText(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                                      EndHyphenEdit::NO_EDIT, advances.data(), nullptr, nullptr));
        ASSERT_EQ(1u, advances.size());
        EXPECT_EQ(1.0f, advances[0]);
    }
    {
        MinikinPaint paint(fc);
        std::vector<uint16_t> text = utf8ToUtf16("IV");
        std::vector<float> advances(text.size());
        Range range(0, text.size());
        EXPECT_EQ(6.0f,
                  Layout::measureText(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                                      EndHyphenEdit::NO_EDIT, advances.data(), nullptr, nullptr));
        ASSERT_EQ(2u, advances.size());
        EXPECT_EQ(1.0f, advances[0]);
        EXPECT_EQ(5.0f, advances[1]);
    }
    {
        MinikinPaint paint(fc);
        std::vector<uint16_t> text = utf8ToUtf16("IVX");
        std::vector<float> advances(text.size());
        Range range(0, text.size());
        EXPECT_EQ(16.0f,
                  Layout::measureText(text, range, Bidi::LTR, paint, StartHyphenEdit::NO_EDIT,
                                      EndHyphenEdit::NO_EDIT, advances.data(), nullptr, nullptr));
        ASSERT_EQ(3u, advances.size());
        EXPECT_EQ(1.0f, advances[0]);
        EXPECT_EQ(5.0f, advances[1]);
        EXPECT_EQ(10.0f, advances[2]);
    }
}

TEST_F(LayoutTest, doLayoutWithPrecomputedPiecesTest) {
    float MARKER1 = 1e+16;
    float MARKER2 = 1e+17;
    auto fc = buildFontCollection("LayoutTestFont.ttf");
    MinikinPaint paint(fc);
    {
        LayoutPieces pieces;

        Layout inLayout = doLayout("I", MinikinPaint(fc));
        inLayout.mAdvances[0] = MARKER1;  // Modify the advance to make sure this layout is used.
        pieces.insert(utf8ToUtf16("I"), Range(0, 1), paint, false /* dir */,
                      StartHyphenEdit::NO_EDIT, EndHyphenEdit::NO_EDIT, inLayout);

        Layout outLayout = doLayoutWithPrecomputedPieces("I", MinikinPaint(fc), pieces);
        EXPECT_EQ(MARKER1, outLayout.mAdvances[0]);
    }
    {
        LayoutPieces pieces;

        Layout inLayout = doLayout("I", MinikinPaint(fc));
        inLayout.mAdvances[0] = MARKER1;
        pieces.insert(utf8ToUtf16("I"), Range(0, 1), paint, false /* dir */,
                      StartHyphenEdit::NO_EDIT, EndHyphenEdit::NO_EDIT, inLayout);

        Layout outLayout = doLayoutWithPrecomputedPieces("II", MinikinPaint(fc), pieces);
        // The layout pieces are used in word units. Should not be used "I" for "II".
        EXPECT_NE(MARKER1, outLayout.mAdvances[0]);
        EXPECT_NE(MARKER1, outLayout.mAdvances[1]);
    }
    {
        LayoutPieces pieces;

        Layout inLayout = doLayout("I", MinikinPaint(fc));
        inLayout.mAdvances[0] = MARKER1;
        pieces.insert(utf8ToUtf16("I"), Range(0, 1), paint, false /* dir */,
                      StartHyphenEdit::NO_EDIT, EndHyphenEdit::NO_EDIT, inLayout);

        Layout outLayout = doLayoutWithPrecomputedPieces("I I", MinikinPaint(fc), pieces);
        EXPECT_EQ(MARKER1, outLayout.mAdvances[0]);
        EXPECT_EQ(MARKER1, outLayout.mAdvances[2]);
    }
    {
        LayoutPieces pieces;

        Layout inLayout = doLayout("I", MinikinPaint(fc));
        inLayout.mAdvances[0] = MARKER1;  // Modify the advance to make sure this layout is used.
        pieces.insert(utf8ToUtf16("I"), Range(0, 1), paint, false /* dir */,
                      StartHyphenEdit::NO_EDIT, EndHyphenEdit::NO_EDIT, inLayout);

        inLayout = doLayout("V", MinikinPaint(fc));
        inLayout.mAdvances[0] = MARKER2;  // Modify the advance to make sure this layout is used.
        pieces.insert(utf8ToUtf16("V"), Range(0, 1), paint, false /* dir */,
                      StartHyphenEdit::NO_EDIT, EndHyphenEdit::NO_EDIT, inLayout);

        Layout outLayout = doLayoutWithPrecomputedPieces("I V", MinikinPaint(fc), pieces);
        EXPECT_EQ(MARKER1, outLayout.mAdvances[0]);
        EXPECT_EQ(MARKER2, outLayout.mAdvances[2]);
    }
}

// TODO: Add more test cases, e.g. measure text, letter spacing.

}  // namespace minikin