services/surfaceflinger/tests/Transaction_test.cpp

/*
 * Copyright (C) 2011 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 <gtest/gtest.h>

#include <android/native_window.h>

#include <gui/ISurfaceComposer.h>
#include <gui/Surface.h>
#include <gui/SurfaceComposerClient.h>
#include <private/gui/ComposerService.h>
#include <private/gui/LayerState.h>

#include <utils/String8.h>
#include <ui/DisplayInfo.h>

#include <math.h>

namespace android {

// Fill an RGBA_8888 formatted surface with a single color.
static void fillSurfaceRGBA8(const sp<SurfaceControl>& sc,
        uint8_t r, uint8_t g, uint8_t b) {
    ANativeWindow_Buffer outBuffer;
    sp<Surface> s = sc->getSurface();
    ASSERT_TRUE(s != NULL);
    ASSERT_EQ(NO_ERROR, s->lock(&outBuffer, NULL));
    uint8_t* img = reinterpret_cast<uint8_t*>(outBuffer.bits);
    for (int y = 0; y < outBuffer.height; y++) {
        for (int x = 0; x < outBuffer.width; x++) {
            uint8_t* pixel = img + (4 * (y*outBuffer.stride + x));
            pixel[0] = r;
            pixel[1] = g;
            pixel[2] = b;
            pixel[3] = 255;
        }
    }
    ASSERT_EQ(NO_ERROR, s->unlockAndPost());
}

// A ScreenCapture is a screenshot from SurfaceFlinger that can be used to check
// individual pixel values for testing purposes.
class ScreenCapture : public RefBase {
public:
    static void captureScreen(sp<ScreenCapture>* sc) {
        sp<IGraphicBufferProducer> producer;
        sp<IGraphicBufferConsumer> consumer;
        BufferQueue::createBufferQueue(&producer, &consumer);
        sp<CpuConsumer> cpuConsumer = new CpuConsumer(consumer, 1);
        sp<ISurfaceComposer> sf(ComposerService::getComposerService());
        sp<IBinder> display(sf->getBuiltInDisplay(
                ISurfaceComposer::eDisplayIdMain));
        SurfaceComposerClient::openGlobalTransaction();
        SurfaceComposerClient::closeGlobalTransaction(true);
        ASSERT_EQ(NO_ERROR, sf->captureScreen(display, producer, Rect(), 0, 0,
                0, INT_MAX, false));
        *sc = new ScreenCapture(cpuConsumer);
    }

    void checkPixel(uint32_t x, uint32_t y, uint8_t r, uint8_t g, uint8_t b) {
        ASSERT_EQ(HAL_PIXEL_FORMAT_RGBA_8888, mBuf.format);
        const uint8_t* img = static_cast<const uint8_t*>(mBuf.data);
        const uint8_t* pixel = img + (4 * (y * mBuf.stride + x));
        if (r != pixel[0] || g != pixel[1] || b != pixel[2]) {
            String8 err(String8::format("pixel @ (%3d, %3d): "
                    "expected [%3d, %3d, %3d], got [%3d, %3d, %3d]",
                    x, y, r, g, b, pixel[0], pixel[1], pixel[2]));
            EXPECT_EQ(String8(), err) << err.string();
        }
    }

    void expectFGColor(uint32_t x, uint32_t y) {
        checkPixel(x, y, 195, 63, 63);
    }

    void expectBGColor(uint32_t x, uint32_t y) {
        checkPixel(x, y, 63, 63, 195);
    }

    void expectChildColor(uint32_t x, uint32_t y) {
        checkPixel(x, y, 200, 200, 200);
    }

private:
    ScreenCapture(const sp<CpuConsumer>& cc) :
        mCC(cc) {
        EXPECT_EQ(NO_ERROR, mCC->lockNextBuffer(&mBuf));
    }

    ~ScreenCapture() {
        mCC->unlockBuffer(mBuf);
    }

    sp<CpuConsumer> mCC;
    CpuConsumer::LockedBuffer mBuf;
};

class LayerUpdateTest : public ::testing::Test {
protected:
    virtual void SetUp() {
        mComposerClient = new SurfaceComposerClient;
        ASSERT_EQ(NO_ERROR, mComposerClient->initCheck());

        sp<IBinder> display(SurfaceComposerClient::getBuiltInDisplay(
                ISurfaceComposer::eDisplayIdMain));
        DisplayInfo info;
        SurfaceComposerClient::getDisplayInfo(display, &info);

        ssize_t displayWidth = info.w;
        ssize_t displayHeight = info.h;

        // Background surface
        mBGSurfaceControl = mComposerClient->createSurface(
                String8("BG Test Surface"), displayWidth, displayHeight,
                PIXEL_FORMAT_RGBA_8888, 0);
        ASSERT_TRUE(mBGSurfaceControl != NULL);
        ASSERT_TRUE(mBGSurfaceControl->isValid());
        fillSurfaceRGBA8(mBGSurfaceControl, 63, 63, 195);

        // Foreground surface
        mFGSurfaceControl = mComposerClient->createSurface(
                String8("FG Test Surface"), 64, 64, PIXEL_FORMAT_RGBA_8888, 0);
        ASSERT_TRUE(mFGSurfaceControl != NULL);
        ASSERT_TRUE(mFGSurfaceControl->isValid());

        fillSurfaceRGBA8(mFGSurfaceControl, 195, 63, 63);

        // Synchronization surface
        mSyncSurfaceControl = mComposerClient->createSurface(
                String8("Sync Test Surface"), 1, 1, PIXEL_FORMAT_RGBA_8888, 0);
        ASSERT_TRUE(mSyncSurfaceControl != NULL);
        ASSERT_TRUE(mSyncSurfaceControl->isValid());

        fillSurfaceRGBA8(mSyncSurfaceControl, 31, 31, 31);

        SurfaceComposerClient::openGlobalTransaction();

        mComposerClient->setDisplayLayerStack(display, 0);

        ASSERT_EQ(NO_ERROR, mBGSurfaceControl->setLayer(INT32_MAX-2));
        ASSERT_EQ(NO_ERROR, mBGSurfaceControl->show());

        ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setLayer(INT32_MAX-1));
        ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setPosition(64, 64));
        ASSERT_EQ(NO_ERROR, mFGSurfaceControl->show());

        ASSERT_EQ(NO_ERROR, mSyncSurfaceControl->setLayer(INT32_MAX-1));
        ASSERT_EQ(NO_ERROR, mSyncSurfaceControl->setPosition(displayWidth-2,
                displayHeight-2));
        ASSERT_EQ(NO_ERROR, mSyncSurfaceControl->show());

        SurfaceComposerClient::closeGlobalTransaction(true);
    }

    virtual void TearDown() {
        mComposerClient->dispose();
        mBGSurfaceControl = 0;
        mFGSurfaceControl = 0;
        mSyncSurfaceControl = 0;
        mComposerClient = 0;
    }

    void waitForPostedBuffers() {
        // Since the sync surface is in synchronous mode (i.e. double buffered)
        // posting three buffers to it should ensure that at least two
        // SurfaceFlinger::handlePageFlip calls have been made, which should
        // guaranteed that a buffer posted to another Surface has been retired.
        fillSurfaceRGBA8(mSyncSurfaceControl, 31, 31, 31);
        fillSurfaceRGBA8(mSyncSurfaceControl, 31, 31, 31);
        fillSurfaceRGBA8(mSyncSurfaceControl, 31, 31, 31);
    }

    sp<SurfaceComposerClient> mComposerClient;
    sp<SurfaceControl> mBGSurfaceControl;
    sp<SurfaceControl> mFGSurfaceControl;

    // This surface is used to ensure that the buffers posted to
    // mFGSurfaceControl have been picked up by SurfaceFlinger.
    sp<SurfaceControl> mSyncSurfaceControl;
};

TEST_F(LayerUpdateTest, LayerMoveWorks) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before move");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(0, 12);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }

    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setPosition(128, 128));
    SurfaceComposerClient::closeGlobalTransaction(true);
    {
        // This should reflect the new position, but not the new color.
        SCOPED_TRACE("after move, before redraw");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectBGColor(75, 75);
        sc->expectFGColor(145, 145);
    }

    fillSurfaceRGBA8(mFGSurfaceControl, 63, 195, 63);
    waitForPostedBuffers();
    {
        // This should reflect the new position and the new color.
        SCOPED_TRACE("after redraw");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectBGColor(75, 75);
        sc->checkPixel(145, 145, 63, 195, 63);
    }
}

TEST_F(LayerUpdateTest, LayerResizeWorks) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before resize");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(0, 12);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }

    ALOGD("resizing");
    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setSize(128, 128));
    SurfaceComposerClient::closeGlobalTransaction(true);
    ALOGD("resized");
    {
        // This should not reflect the new size or color because SurfaceFlinger
        // has not yet received a buffer of the correct size.
        SCOPED_TRACE("after resize, before redraw");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(0, 12);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }

    ALOGD("drawing");
    fillSurfaceRGBA8(mFGSurfaceControl, 63, 195, 63);
    waitForPostedBuffers();
    ALOGD("drawn");
    {
        // This should reflect the new size and the new color.
        SCOPED_TRACE("after redraw");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->checkPixel(75, 75, 63, 195, 63);
        sc->checkPixel(145, 145, 63, 195, 63);
    }
}

TEST_F(LayerUpdateTest, LayerCropWorks) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before crop");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }

    SurfaceComposerClient::openGlobalTransaction();
    Rect cropRect(16, 16, 32, 32);
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setCrop(cropRect));
    SurfaceComposerClient::closeGlobalTransaction(true);
    {
        // This should crop the foreground surface.
        SCOPED_TRACE("after crop");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectBGColor(75, 75);
        sc->expectFGColor(95, 80);
        sc->expectFGColor(80, 95);
        sc->expectBGColor(96, 96);
    }
}

TEST_F(LayerUpdateTest, LayerFinalCropWorks) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before crop");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }
    SurfaceComposerClient::openGlobalTransaction();
    Rect cropRect(16, 16, 32, 32);
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setFinalCrop(cropRect));
    SurfaceComposerClient::closeGlobalTransaction(true);
    {
        // This should crop the foreground surface.
        SCOPED_TRACE("after crop");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectBGColor(75, 75);
        sc->expectBGColor(95, 80);
        sc->expectBGColor(80, 95);
        sc->expectBGColor(96, 96);
    }
}

TEST_F(LayerUpdateTest, LayerSetLayerWorks) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before setLayer");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }

    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setLayer(INT_MAX - 3));
    SurfaceComposerClient::closeGlobalTransaction(true);
    {
        // This should hide the foreground surface beneath the background.
        SCOPED_TRACE("after setLayer");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectBGColor(75, 75);
        sc->expectBGColor(145, 145);
    }
}

TEST_F(LayerUpdateTest, LayerShowHideWorks) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before hide");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }

    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->hide());
    SurfaceComposerClient::closeGlobalTransaction(true);
    {
        // This should hide the foreground surface.
        SCOPED_TRACE("after hide, before show");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectBGColor(75, 75);
        sc->expectBGColor(145, 145);
    }

    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->show());
    SurfaceComposerClient::closeGlobalTransaction(true);
    {
        // This should show the foreground surface.
        SCOPED_TRACE("after show");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }
}

TEST_F(LayerUpdateTest, LayerSetAlphaWorks) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before setAlpha");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }

    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setAlpha(0.75f));
    SurfaceComposerClient::closeGlobalTransaction(true);
    {
        // This should set foreground to be 75% opaque.
        SCOPED_TRACE("after setAlpha");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->checkPixel(75, 75, 162, 63, 96);
        sc->expectBGColor(145, 145);
    }
}

TEST_F(LayerUpdateTest, LayerSetLayerStackWorks) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before setLayerStack");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }

    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setLayerStack(1));
    SurfaceComposerClient::closeGlobalTransaction(true);
    {
        // This should hide the foreground surface since it goes to a different
        // layer stack.
        SCOPED_TRACE("after setLayerStack");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectBGColor(75, 75);
        sc->expectBGColor(145, 145);
    }
}

TEST_F(LayerUpdateTest, LayerSetFlagsWorks) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before setFlags");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectFGColor(75, 75);
        sc->expectBGColor(145, 145);
    }

    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setFlags(
            layer_state_t::eLayerHidden, layer_state_t::eLayerHidden));
    SurfaceComposerClient::closeGlobalTransaction(true);
    {
        // This should hide the foreground surface
        SCOPED_TRACE("after setFlags");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectBGColor(75, 75);
        sc->expectBGColor(145, 145);
    }
}

TEST_F(LayerUpdateTest, LayerSetMatrixWorks) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before setMatrix");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectFGColor(91, 96);
        sc->expectFGColor(96, 101);
        sc->expectBGColor(145, 145);
    }

    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setMatrix(M_SQRT1_2, M_SQRT1_2,
            -M_SQRT1_2, M_SQRT1_2));
    SurfaceComposerClient::closeGlobalTransaction(true);
    {
        SCOPED_TRACE("after setMatrix");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(24, 24);
        sc->expectFGColor(91, 96);
        sc->expectBGColor(96, 91);
        sc->expectBGColor(145, 145);
    }
}

TEST_F(LayerUpdateTest, DeferredTransactionTest) {
    sp<ScreenCapture> sc;
    {
        SCOPED_TRACE("before anything");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(32, 32);
        sc->expectFGColor(96, 96);
        sc->expectBGColor(160, 160);
    }

    // set up two deferred transactions on different frames
    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setAlpha(0.75));
    mFGSurfaceControl->deferTransactionUntil(mSyncSurfaceControl->getHandle(),
            mSyncSurfaceControl->getSurface()->getNextFrameNumber());
    SurfaceComposerClient::closeGlobalTransaction(true);

    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setPosition(128,128));
    mFGSurfaceControl->deferTransactionUntil(mSyncSurfaceControl->getHandle(),
            mSyncSurfaceControl->getSurface()->getNextFrameNumber() + 1);
    SurfaceComposerClient::closeGlobalTransaction(true);

    {
        SCOPED_TRACE("before any trigger");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(32, 32);
        sc->expectFGColor(96, 96);
        sc->expectBGColor(160, 160);
    }

    // should trigger the first deferred transaction, but not the second one
    fillSurfaceRGBA8(mSyncSurfaceControl, 31, 31, 31);
    {
        SCOPED_TRACE("after first trigger");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(32, 32);
        sc->checkPixel(96, 96, 162, 63, 96);
        sc->expectBGColor(160, 160);
    }

    // should show up immediately since it's not deferred
    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setAlpha(1.0));
    SurfaceComposerClient::closeGlobalTransaction(true);

    // trigger the second deferred transaction
    fillSurfaceRGBA8(mSyncSurfaceControl, 31, 31, 31);
    {
        SCOPED_TRACE("after second trigger");
        ScreenCapture::captureScreen(&sc);
        sc->expectBGColor(32, 32);
        sc->expectBGColor(96, 96);
        sc->expectFGColor(160, 160);
    }
}

class ChildLayerTest : public LayerUpdateTest {
protected:
    void SetUp() override {
        LayerUpdateTest::SetUp();
        mChild = mComposerClient->createSurface(
                String8("Child surface"),
                10, 10, PIXEL_FORMAT_RGBA_8888,
                0, mFGSurfaceControl.get());
        fillSurfaceRGBA8(mChild, 200, 200, 200);

        {
            SCOPED_TRACE("before anything");
            ScreenCapture::captureScreen(&mCapture);
            mCapture->expectChildColor(64, 64);
        }
    }
    void TearDown() override {
        LayerUpdateTest::TearDown();
        mChild = 0;
    }

    sp<SurfaceControl> mChild;
    sp<ScreenCapture> mCapture;
};

TEST_F(ChildLayerTest, ChildLayerPositioning) {
    SurfaceComposerClient::openGlobalTransaction();
    mChild->show();
    mChild->setPosition(10, 10);
    mFGSurfaceControl->setPosition(64, 64);
    SurfaceComposerClient::closeGlobalTransaction(true);

    {
        ScreenCapture::captureScreen(&mCapture);
        // Top left of foreground must now be visible
        mCapture->expectFGColor(64, 64);
        // But 10 pixels in we should see the child surface
        mCapture->expectChildColor(74, 74);
        // And 10 more pixels we should be back to the foreground surface
        mCapture->expectFGColor(84, 84);
    }

    SurfaceComposerClient::openGlobalTransaction();
    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setPosition(0, 0));
    SurfaceComposerClient::closeGlobalTransaction(true);

    {
        ScreenCapture::captureScreen(&mCapture);
        // Top left of foreground should now be at 0, 0
        mCapture->expectFGColor(0, 0);
        // But 10 pixels in we should see the child surface
        mCapture->expectChildColor(10, 10);
        // And 10 more pixels we should be back to the foreground surface
        mCapture->expectFGColor(20, 20);
    }
}

TEST_F(ChildLayerTest, ChildLayerConstraints) {
    SurfaceComposerClient::openGlobalTransaction();
    mChild->show();
    mFGSurfaceControl->setPosition(0, 0);
    mChild->setPosition(63, 63);
    SurfaceComposerClient::closeGlobalTransaction(true);

    {
        ScreenCapture::captureScreen(&mCapture);
        mCapture->expectFGColor(0, 0);
        // Last pixel in foreground should now be the child.
        mCapture->expectChildColor(63, 63);
        // But the child should be constrained and the next pixel
        // must be the background
        mCapture->expectBGColor(64, 64);
    }
}

TEST_F(ChildLayerTest, ChildLayerScaling) {
    SurfaceComposerClient::openGlobalTransaction();
    mFGSurfaceControl->setPosition(0, 0);
    SurfaceComposerClient::closeGlobalTransaction(true);

    // Find the boundary between the parent and child
    {
        ScreenCapture::captureScreen(&mCapture);
        mCapture->expectChildColor(9, 9);
        mCapture->expectFGColor(10, 10);
    }

    SurfaceComposerClient::openGlobalTransaction();
    mFGSurfaceControl->setMatrix(2.0, 0, 0, 2.0);
    SurfaceComposerClient::closeGlobalTransaction(true);

    // The boundary should be twice as far from the origin now.
    // The pixels from the last test should all be child now
    {
        ScreenCapture::captureScreen(&mCapture);
        mCapture->expectChildColor(9, 9);
        mCapture->expectChildColor(10, 10);
        mCapture->expectChildColor(19, 19);
        mCapture->expectFGColor(20, 20);
    }
}

TEST_F(ChildLayerTest, ReparentChildren) {
    SurfaceComposerClient::openGlobalTransaction();
    mChild->show();
    mChild->setPosition(10, 10);
    mFGSurfaceControl->setPosition(64, 64);
    SurfaceComposerClient::closeGlobalTransaction(true);

    {
        ScreenCapture::captureScreen(&mCapture);
        // Top left of foreground must now be visible
        mCapture->expectFGColor(64, 64);
        // But 10 pixels in we should see the child surface
        mCapture->expectChildColor(74, 74);
        // And 10 more pixels we should be back to the foreground surface
        mCapture->expectFGColor(84, 84);
    }
    mFGSurfaceControl->reparentChildren(mBGSurfaceControl->getHandle());
    {
        ScreenCapture::captureScreen(&mCapture);
        mCapture->expectFGColor(64, 64);
        // In reparenting we should have exposed the entire foreground surface.
        mCapture->expectFGColor(74, 74);
        // And the child layer should now begin at 10, 10 (since the BG
        // layer is at (0, 0)).
        mCapture->expectBGColor(9, 9);
        mCapture->expectChildColor(10, 10);
    }
}

TEST_F(ChildLayerTest, DetachChildren) {
    SurfaceComposerClient::openGlobalTransaction();
    mChild->show();
    mChild->setPosition(10, 10);
    mFGSurfaceControl->setPosition(64, 64);
    SurfaceComposerClient::closeGlobalTransaction(true);

    {
        ScreenCapture::captureScreen(&mCapture);
        // Top left of foreground must now be visible
        mCapture->expectFGColor(64, 64);
        // But 10 pixels in we should see the child surface
        mCapture->expectChildColor(74, 74);
        // And 10 more pixels we should be back to the foreground surface
        mCapture->expectFGColor(84, 84);
    }

    SurfaceComposerClient::openGlobalTransaction();
    mFGSurfaceControl->detachChildren();
    SurfaceComposerClient::closeGlobalTransaction();

    SurfaceComposerClient::openGlobalTransaction();
    mChild->hide();
    SurfaceComposerClient::closeGlobalTransaction();

    // Nothing should have changed.
    {
        ScreenCapture::captureScreen(&mCapture);
        mCapture->expectFGColor(64, 64);
        mCapture->expectChildColor(74, 74);
        mCapture->expectFGColor(84, 84);
    }
}

}