libreoffice/vcl/qa/cppunit/pdfexport/pdfexport.cxx

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#include <config_features.h>

#include <com/sun/star/frame/Desktop.hpp>
#include <com/sun/star/frame/XStorable.hpp>

#include <comphelper/processfactory.hxx>
#include <comphelper/propertyvalue.hxx>
#include <cppuhelper/implbase.hxx>
#include <test/bootstrapfixture.hxx>
#include <unotest/macros_test.hxx>
#include <unotools/mediadescriptor.hxx>
#include <unotools/tempfile.hxx>
#include <vcl/filter/pdfdocument.hxx>
#include <tools/zcodec.hxx>

using namespace ::com::sun::star;

namespace
{

const char* const DATA_DIRECTORY = "/vcl/qa/cppunit/pdfexport/data/";

/// Tests the PDF export filter.
class PdfExportTest : public test::BootstrapFixture, public unotest::MacrosTest
{
    uno::Reference<uno::XComponentContext> mxComponentContext;
    uno::Reference<lang::XComponent> mxComponent;

public:
    virtual void setUp() override;
    virtual void tearDown() override;
#if HAVE_FEATURE_PDFIUM
    void load(const OUString& rFile, vcl::filter::PDFDocument& rDocument);
    /// Tests that a pdf image is roundtripped back to PDF as a vector format.
    void testTdf106059();
    /// Tests that text highlight from Impress is not lost.
    void testTdf105461();
    /// Tests that embedded video from Impress is not exported as a linked one.
    void testTdf105093();
    /// Tests export of non-PDF images.
    void testTdf106206();
    /// Tests export of PDF images without reference XObjects.
    void testTdf106693();
    void testTdf106972();
    void testTdf106972Pdf17();
    void testTdf107013();
    void testTdf107018();
    void testTdf107089();
#endif

    CPPUNIT_TEST_SUITE(PdfExportTest);
#if HAVE_FEATURE_PDFIUM
    CPPUNIT_TEST(testTdf106059);
    CPPUNIT_TEST(testTdf105461);
    CPPUNIT_TEST(testTdf105093);
    CPPUNIT_TEST(testTdf106206);
    CPPUNIT_TEST(testTdf106693);
    CPPUNIT_TEST(testTdf106972);
    CPPUNIT_TEST(testTdf106972Pdf17);
    CPPUNIT_TEST(testTdf107013);
    CPPUNIT_TEST(testTdf107018);
    CPPUNIT_TEST(testTdf107089);
#endif
    CPPUNIT_TEST_SUITE_END();
};

void PdfExportTest::setUp()
{
    test::BootstrapFixture::setUp();

    mxComponentContext.set(comphelper::getComponentContext(getMultiServiceFactory()));
    mxDesktop.set(frame::Desktop::create(mxComponentContext));
}

void PdfExportTest::tearDown()
{
    if (mxComponent.is())
        mxComponent->dispose();

    test::BootstrapFixture::tearDown();
}

#if HAVE_FEATURE_PDFIUM

void PdfExportTest::load(const OUString& rFile, vcl::filter::PDFDocument& rDocument)
{
    // Import the bugdoc and export as PDF.
    OUString aURL = m_directories.getURLFromSrc(DATA_DIRECTORY) + rFile;
    mxComponent = loadFromDesktop(aURL);
    CPPUNIT_ASSERT(mxComponent.is());

    uno::Reference<frame::XStorable> xStorable(mxComponent, uno::UNO_QUERY);
    utl::TempFile aTempFile;
    aTempFile.EnableKillingFile();
    utl::MediaDescriptor aMediaDescriptor;
    aMediaDescriptor["FilterName"] <<= OUString("writer_pdf_Export");
    xStorable->storeToURL(aTempFile.GetURL(), aMediaDescriptor.getAsConstPropertyValueList());

    // Parse the export result.
    SvFileStream aStream(aTempFile.GetURL(), StreamMode::READ);
    CPPUNIT_ASSERT(rDocument.Read(aStream));
}

void PdfExportTest::testTdf106059()
{
    // Import the bugdoc and export as PDF.
    OUString aURL = m_directories.getURLFromSrc(DATA_DIRECTORY) + "tdf106059.odt";
    mxComponent = loadFromDesktop(aURL);
    CPPUNIT_ASSERT(mxComponent.is());

    uno::Reference<frame::XStorable> xStorable(mxComponent, uno::UNO_QUERY);
    utl::TempFile aTempFile;
    aTempFile.EnableKillingFile();
    utl::MediaDescriptor aMediaDescriptor;
    aMediaDescriptor["FilterName"] <<= OUString("writer_pdf_Export");
    // Explicitly enable the usage of the reference XObject markup.
    uno::Sequence<beans::PropertyValue> aFilterData =
    {
        comphelper::makePropertyValue("UseReferenceXObject", true)
    };
    aMediaDescriptor["FilterData"] <<= aFilterData;
    xStorable->storeToURL(aTempFile.GetURL(), aMediaDescriptor.getAsConstPropertyValueList());

    // Parse the export result.
    vcl::filter::PDFDocument aDocument;
    SvFileStream aStream(aTempFile.GetURL(), StreamMode::READ);
    CPPUNIT_ASSERT(aDocument.Read(aStream));

    // Assert that the XObject in the page resources dictionary is a reference XObject.
    std::vector<vcl::filter::PDFObjectElement*> aPages = aDocument.GetPages();
    // The document has one page.
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());
    vcl::filter::PDFObjectElement* pResources = aPages[0]->LookupObject("Resources");
    CPPUNIT_ASSERT(pResources);
    auto pXObjects = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pResources->Lookup("XObject"));
    CPPUNIT_ASSERT(pXObjects);
    // The page has one image.
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), pXObjects->GetItems().size());
    vcl::filter::PDFObjectElement* pReferenceXObject = pXObjects->LookupObject(pXObjects->GetItems().begin()->first);
    CPPUNIT_ASSERT(pReferenceXObject);
    // The image is a reference XObject.
    // This dictionary key was missing, so the XObject wasn't a reference one.
    CPPUNIT_ASSERT(pReferenceXObject->Lookup("Ref"));
}

void PdfExportTest::testTdf106693()
{
    vcl::filter::PDFDocument aDocument;
    load("tdf106693.odt", aDocument);

    // Assert that the XObject in the page resources dictionary is a form XObject.
    std::vector<vcl::filter::PDFObjectElement*> aPages = aDocument.GetPages();
    // The document has one page.
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());
    vcl::filter::PDFObjectElement* pResources = aPages[0]->LookupObject("Resources");
    CPPUNIT_ASSERT(pResources);
    auto pXObjects = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pResources->Lookup("XObject"));
    CPPUNIT_ASSERT(pXObjects);
    // The page has one image.
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), pXObjects->GetItems().size());
    vcl::filter::PDFObjectElement* pXObject = pXObjects->LookupObject(pXObjects->GetItems().begin()->first);
    CPPUNIT_ASSERT(pXObject);
    // The image is a form XObject.
    auto pSubtype = dynamic_cast<vcl::filter::PDFNameElement*>(pXObject->Lookup("Subtype"));
    CPPUNIT_ASSERT(pSubtype);
    CPPUNIT_ASSERT_EQUAL(OString("Form"), pSubtype->GetValue());
    // This failed: UseReferenceXObject was ignored and Ref was always created.
    CPPUNIT_ASSERT(!pXObject->Lookup("Ref"));

    // Assert that the form object refers to an inner form object, not a
    // bitmap.
    auto pInnerResources = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pXObject->Lookup("Resources"));
    CPPUNIT_ASSERT(pInnerResources);
    auto pInnerXObjects = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pInnerResources->LookupElement("XObject"));
    CPPUNIT_ASSERT(pInnerXObjects);
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), pInnerXObjects->GetItems().size());
    vcl::filter::PDFObjectElement* pInnerXObject = pInnerXObjects->LookupObject(pInnerXObjects->GetItems().begin()->first);
    CPPUNIT_ASSERT(pInnerXObject);
    auto pInnerSubtype = dynamic_cast<vcl::filter::PDFNameElement*>(pInnerXObject->Lookup("Subtype"));
    CPPUNIT_ASSERT(pInnerSubtype);
    // This failed: this was Image (bitmap), not Form (vector).
    CPPUNIT_ASSERT_EQUAL(OString("Form"), pInnerSubtype->GetValue());
}

void PdfExportTest::testTdf105461()
{
    vcl::filter::PDFDocument aDocument;
    load("tdf105461.odp", aDocument);

    // The document has one page.
    std::vector<vcl::filter::PDFObjectElement*> aPages = aDocument.GetPages();
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());

    // The page has a stream.
    vcl::filter::PDFObjectElement* pContents = aPages[0]->LookupObject("Contents");
    CPPUNIT_ASSERT(pContents);
    vcl::filter::PDFStreamElement* pStream = pContents->GetStream();
    CPPUNIT_ASSERT(pStream);
    SvMemoryStream& rObjectStream = pStream->GetMemory();
    // Uncompress it.
    SvMemoryStream aUncompressed;
    ZCodec aZCodec;
    aZCodec.BeginCompression();
    rObjectStream.Seek(0);
    aZCodec.Decompress(rObjectStream, aUncompressed);
    CPPUNIT_ASSERT(aZCodec.EndCompression());

    // Make sure there is a filled rectangle inside.
    OString aFilledRectangle("re f*");
    auto pStart = static_cast<const char*>(aUncompressed.GetData());
    const char* pEnd = pStart + aUncompressed.GetSize();
    auto it = std::search(pStart, pEnd, aFilledRectangle.getStr(), aFilledRectangle.getStr() + aFilledRectangle.getLength());
    // This failed, stream contained no filled rectangle.
    CPPUNIT_ASSERT(it != pEnd);
}

void PdfExportTest::testTdf105093()
{
    vcl::filter::PDFDocument aDocument;
    load("tdf105093.odp", aDocument);

    // The document has one page.
    std::vector<vcl::filter::PDFObjectElement*> aPages = aDocument.GetPages();
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());

    // Get page annotations.
    auto pAnnots = dynamic_cast<vcl::filter::PDFArrayElement*>(aPages[0]->Lookup("Annots"));
    CPPUNIT_ASSERT(pAnnots);
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), pAnnots->GetElements().size());
    auto pAnnotReference = dynamic_cast<vcl::filter::PDFReferenceElement*>(pAnnots->GetElements()[0]);
    CPPUNIT_ASSERT(pAnnotReference);
    vcl::filter::PDFObjectElement* pAnnot = pAnnotReference->LookupObject();
    CPPUNIT_ASSERT(pAnnot);
    CPPUNIT_ASSERT_EQUAL(OString("Annot"), static_cast<vcl::filter::PDFNameElement*>(pAnnot->Lookup("Type"))->GetValue());

    // Get the Action -> Rendition -> MediaClip -> FileSpec.
    auto pAction = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pAnnot->Lookup("A"));
    CPPUNIT_ASSERT(pAction);
    auto pRendition = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pAction->LookupElement("R"));
    CPPUNIT_ASSERT(pRendition);
    auto pMediaClip = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pRendition->LookupElement("C"));
    CPPUNIT_ASSERT(pMediaClip);
    auto pFileSpec = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pMediaClip->LookupElement("D"));
    CPPUNIT_ASSERT(pFileSpec);
    // Make sure the filespec refers to an embedded file.
    // This key was missing, the embedded video was handled as a linked one.
    CPPUNIT_ASSERT(pFileSpec->LookupElement("EF"));
}

void PdfExportTest::testTdf106206()
{
    // Import the bugdoc and export as PDF.
    OUString aURL = m_directories.getURLFromSrc(DATA_DIRECTORY) + "tdf106206.odt";
    mxComponent = loadFromDesktop(aURL);
    CPPUNIT_ASSERT(mxComponent.is());

    uno::Reference<frame::XStorable> xStorable(mxComponent, uno::UNO_QUERY);
    utl::TempFile aTempFile;
    aTempFile.EnableKillingFile();
    utl::MediaDescriptor aMediaDescriptor;
    aMediaDescriptor["FilterName"] <<= OUString("writer_pdf_Export");
    xStorable->storeToURL(aTempFile.GetURL(), aMediaDescriptor.getAsConstPropertyValueList());

    // Parse the export result.
    vcl::filter::PDFDocument aDocument;
    SvFileStream aStream(aTempFile.GetURL(), StreamMode::READ);
    CPPUNIT_ASSERT(aDocument.Read(aStream));

    // The document has one page.
    std::vector<vcl::filter::PDFObjectElement*> aPages = aDocument.GetPages();
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());

    // The page has a stream.
    vcl::filter::PDFObjectElement* pContents = aPages[0]->LookupObject("Contents");
    CPPUNIT_ASSERT(pContents);
    vcl::filter::PDFStreamElement* pStream = pContents->GetStream();
    CPPUNIT_ASSERT(pStream);
    SvMemoryStream& rObjectStream = pStream->GetMemory();
    // Uncompress it.
    SvMemoryStream aUncompressed;
    ZCodec aZCodec;
    aZCodec.BeginCompression();
    rObjectStream.Seek(0);
    aZCodec.Decompress(rObjectStream, aUncompressed);
    CPPUNIT_ASSERT(aZCodec.EndCompression());

    // Make sure there is an image reference there.
    OString aImage("/Im");
    auto pStart = static_cast<const char*>(aUncompressed.GetData());
    const char* pEnd = pStart + aUncompressed.GetSize();
    auto it = std::search(pStart, pEnd, aImage.getStr(), aImage.getStr() + aImage.getLength());
    CPPUNIT_ASSERT(it != pEnd);

    // And also that it's not an invalid one.
    OString aInvalidImage("/Im0");
    it = std::search(pStart, pEnd, aInvalidImage.getStr(), aInvalidImage.getStr() + aInvalidImage.getLength());
    // This failed, object #0 was referenced.
    CPPUNIT_ASSERT(bool(it == pEnd));
}

void PdfExportTest::testTdf106972()
{
    // Import the bugdoc and export as PDF.
    OUString aURL = m_directories.getURLFromSrc(DATA_DIRECTORY) + "tdf106972.odt";
    mxComponent = loadFromDesktop(aURL);
    CPPUNIT_ASSERT(mxComponent.is());

    uno::Reference<frame::XStorable> xStorable(mxComponent, uno::UNO_QUERY);
    utl::TempFile aTempFile;
    aTempFile.EnableKillingFile();
    utl::MediaDescriptor aMediaDescriptor;
    aMediaDescriptor["FilterName"] <<= OUString("writer_pdf_Export");
    xStorable->storeToURL(aTempFile.GetURL(), aMediaDescriptor.getAsConstPropertyValueList());

    // Parse the export result.
    vcl::filter::PDFDocument aDocument;
    SvFileStream aStream(aTempFile.GetURL(), StreamMode::READ);
    CPPUNIT_ASSERT(aDocument.Read(aStream));

    // Get access to the only form object on the only page.
    std::vector<vcl::filter::PDFObjectElement*> aPages = aDocument.GetPages();
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());
    vcl::filter::PDFObjectElement* pResources = aPages[0]->LookupObject("Resources");
    CPPUNIT_ASSERT(pResources);
    auto pXObjects = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pResources->Lookup("XObject"));
    CPPUNIT_ASSERT(pXObjects);
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), pXObjects->GetItems().size());
    vcl::filter::PDFObjectElement* pXObject = pXObjects->LookupObject(pXObjects->GetItems().begin()->first);
    CPPUNIT_ASSERT(pXObject);

    // Get access to the only image inside the form object.
    auto pFormResources = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pXObject->Lookup("Resources"));
    CPPUNIT_ASSERT(pFormResources);
    auto pImages = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pFormResources->LookupElement("XObject"));
    CPPUNIT_ASSERT(pImages);
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), pImages->GetItems().size());
    vcl::filter::PDFObjectElement* pImage = pImages->LookupObject(pImages->GetItems().begin()->first);
    CPPUNIT_ASSERT(pImage);

    // Assert resources of the image.
    auto pImageResources = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pImage->Lookup("Resources"));
    CPPUNIT_ASSERT(pImageResources);
    // This failed: the PDF image had no Font resource.
    CPPUNIT_ASSERT(pImageResources->LookupElement("Font"));
}

void PdfExportTest::testTdf106972Pdf17()
{
    // Import the bugdoc and export as PDF.
    OUString aURL = m_directories.getURLFromSrc(DATA_DIRECTORY) + "tdf106972-pdf17.odt";
    mxComponent = loadFromDesktop(aURL);
    CPPUNIT_ASSERT(mxComponent.is());

    uno::Reference<frame::XStorable> xStorable(mxComponent, uno::UNO_QUERY);
    utl::TempFile aTempFile;
    aTempFile.EnableKillingFile();
    utl::MediaDescriptor aMediaDescriptor;
    aMediaDescriptor["FilterName"] <<= OUString("writer_pdf_Export");
    xStorable->storeToURL(aTempFile.GetURL(), aMediaDescriptor.getAsConstPropertyValueList());

    // Parse the export result.
    vcl::filter::PDFDocument aDocument;
    SvFileStream aStream(aTempFile.GetURL(), StreamMode::READ);
    CPPUNIT_ASSERT(aDocument.Read(aStream));

    // Get access to the only image on the only page.
    std::vector<vcl::filter::PDFObjectElement*> aPages = aDocument.GetPages();
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());
    vcl::filter::PDFObjectElement* pResources = aPages[0]->LookupObject("Resources");
    CPPUNIT_ASSERT(pResources);
    auto pXObjects = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pResources->Lookup("XObject"));
    CPPUNIT_ASSERT(pXObjects);
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), pXObjects->GetItems().size());
    vcl::filter::PDFObjectElement* pXObject = pXObjects->LookupObject(pXObjects->GetItems().begin()->first);
    CPPUNIT_ASSERT(pXObject);

    // Assert that we now attempt to preserve the original PDF data, even if
    // the original input was PDF >= 1.4.
    CPPUNIT_ASSERT(pXObject->Lookup("Resources"));
}

void PdfExportTest::testTdf107013()
{
    vcl::filter::PDFDocument aDocument;
    load("tdf107013.odt", aDocument);

    // Get access to the only image on the only page.
    std::vector<vcl::filter::PDFObjectElement*> aPages = aDocument.GetPages();
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());
    vcl::filter::PDFObjectElement* pResources = aPages[0]->LookupObject("Resources");
    CPPUNIT_ASSERT(pResources);
    auto pXObjects = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pResources->Lookup("XObject"));
    CPPUNIT_ASSERT(pXObjects);
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), pXObjects->GetItems().size());
    vcl::filter::PDFObjectElement* pXObject = pXObjects->LookupObject(pXObjects->GetItems().begin()->first);
    // This failed, the reference to the image was created, but not the image.
    CPPUNIT_ASSERT(pXObject);
}

void PdfExportTest::testTdf107018()
{
    vcl::filter::PDFDocument aDocument;
    load("tdf107018.odt", aDocument);

    // Get access to the only image on the only page.
    std::vector<vcl::filter::PDFObjectElement*> aPages = aDocument.GetPages();
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());
    vcl::filter::PDFObjectElement* pResources = aPages[0]->LookupObject("Resources");
    CPPUNIT_ASSERT(pResources);
    auto pXObjects = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pResources->Lookup("XObject"));
    CPPUNIT_ASSERT(pXObjects);
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), pXObjects->GetItems().size());
    vcl::filter::PDFObjectElement* pXObject = pXObjects->LookupObject(pXObjects->GetItems().begin()->first);
    CPPUNIT_ASSERT(pXObject);

    // Get access to the form object inside the image.
    auto pXObjectResources = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pXObject->Lookup("Resources"));
    CPPUNIT_ASSERT(pXObjectResources);
    auto pXObjectForms = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pXObjectResources->LookupElement("XObject"));
    CPPUNIT_ASSERT(pXObjectForms);
    vcl::filter::PDFObjectElement* pForm = pXObjectForms->LookupObject(pXObjectForms->GetItems().begin()->first);
    CPPUNIT_ASSERT(pForm);

    // Get access to Resources -> Font -> F1 of the form.
    auto pFormResources = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pForm->Lookup("Resources"));
    CPPUNIT_ASSERT(pFormResources);
    auto pFonts = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pFormResources->LookupElement("Font"));
    CPPUNIT_ASSERT(pFonts);
    auto pF1Ref = dynamic_cast<vcl::filter::PDFReferenceElement*>(pFonts->LookupElement("F1"));
    CPPUNIT_ASSERT(pF1Ref);
    vcl::filter::PDFObjectElement* pF1 = pF1Ref->LookupObject();
    CPPUNIT_ASSERT(pF1);

    // Check that Foo -> Bar of the font is of type Pages.
    auto pFontFoo = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pF1->Lookup("Foo"));
    CPPUNIT_ASSERT(pFontFoo);
    auto pBar = dynamic_cast<vcl::filter::PDFReferenceElement*>(pFontFoo->LookupElement("Bar"));
    CPPUNIT_ASSERT(pBar);
    vcl::filter::PDFObjectElement* pObject = pBar->LookupObject();
    CPPUNIT_ASSERT(pObject);
    auto pName = dynamic_cast<vcl::filter::PDFNameElement*>(pObject->Lookup("Type"));
    CPPUNIT_ASSERT(pName);
    // This was "XObject", reference in a nested dictionary wasn't updated when
    // copying the page stream of a PDF image.
    CPPUNIT_ASSERT_EQUAL(OString("Pages"), pName->GetValue());
}

void PdfExportTest::testTdf107089()
{
    vcl::filter::PDFDocument aDocument;
    load("tdf107089.odt", aDocument);

    // Get access to the only image on the only page.
    std::vector<vcl::filter::PDFObjectElement*> aPages = aDocument.GetPages();
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());
    vcl::filter::PDFObjectElement* pResources = aPages[0]->LookupObject("Resources");
    CPPUNIT_ASSERT(pResources);
    auto pXObjects = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pResources->Lookup("XObject"));
    CPPUNIT_ASSERT(pXObjects);
    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), pXObjects->GetItems().size());
    vcl::filter::PDFObjectElement* pXObject = pXObjects->LookupObject(pXObjects->GetItems().begin()->first);
    CPPUNIT_ASSERT(pXObject);

    // Get access to the form object inside the image.
    auto pXObjectResources = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pXObject->Lookup("Resources"));
    CPPUNIT_ASSERT(pXObjectResources);
    auto pXObjectForms = dynamic_cast<vcl::filter::PDFDictionaryElement*>(pXObjectResources->LookupElement("XObject"));
    CPPUNIT_ASSERT(pXObjectForms);
    vcl::filter::PDFObjectElement* pForm = pXObjectForms->LookupObject(pXObjectForms->GetItems().begin()->first);
    CPPUNIT_ASSERT(pForm);

    // Make sure 'Hello' is part of the form object's stream.
    vcl::filter::PDFStreamElement* pStream = pForm->GetStream();
    CPPUNIT_ASSERT(pStream);
    SvMemoryStream& rObjectStream = pStream->GetMemory();
    OString aHello("Hello");
    auto pStart = static_cast<const char*>(rObjectStream.GetData());
    const char* pEnd = pStart + rObjectStream.GetSize();
    auto it = std::search(pStart, pEnd, aHello.getStr(), aHello.getStr() + aHello.getLength());
    // This failed, 'Hello' was part only a mixed compressed/uncompressed stream, i.e. garbage.
    CPPUNIT_ASSERT(it != pEnd);
}
#endif

CPPUNIT_TEST_SUITE_REGISTRATION(PdfExportTest);

}

CPPUNIT_PLUGIN_IMPLEMENT();

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