chromeos/utils/pdf_conversion_unittest.cc

// Copyright 2021 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 "chromeos/utils/pdf_conversion.h"

#include <fstream>
#include <string>
#include <vector>

#include "base/files/file_util.h"
#include "base/files/scoped_temp_dir.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "third_party/skia/include/core/SkBitmap.h"
#include "ui/gfx/image/image.h"
#include "ui/gfx/image/image_unittest_util.h"
#include "ui/gfx/image/image_util.h"

namespace chromeos {

namespace {

// Returns a manually generated JPG image with specified width and height in
// pixels.
std::vector<uint8_t> CreateJpg(int width, int height) {
  gfx::Image original = gfx::test::CreateImage(width, height);
  std::vector<uint8_t> jpg_buffer;
  if (!gfx::JPEG1xEncodedDataFromImage(original, 80, &jpg_buffer)) {
    return {};
  }
  return jpg_buffer;
}

}  // namespace

using ConvertToPdfTest = testing::Test;

// Test that JPG image can be converted to pdf file successfully.
TEST_F(ConvertToPdfTest, ToFileNoDpi) {
  std::vector<std::string> images;
  std::vector<uint8_t> bytes = CreateJpg(100, 100);
  images.push_back(std::string(bytes.begin(), bytes.end()));

  base::ScopedTempDir temp_dir;
  ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
  auto output_path = temp_dir.GetPath().Append("temp.pdf");

  EXPECT_TRUE(ConvertJpgImagesToPdf(images, output_path,
                                    /*rotate_alternate_pages=*/false,
                                    /*dpi=*/absl::nullopt));
  EXPECT_TRUE(base::PathExists(output_path));

  int64_t file_size;
  EXPECT_TRUE(base::GetFileSize(output_path, &file_size));

  // Smallest PDF should be at least 20 bytes.
  EXPECT_GT(file_size, 20u);
}

// Test that JPG image can be converted to pdf file successfully when scanner
// DPI is specified. Higher DPI results in larger pixel counts, but should
// result in the same PDF page size.
TEST_F(ConvertToPdfTest, ToFileWithDpi) {
  base::ScopedTempDir temp_dir;
  ASSERT_TRUE(temp_dir.CreateUniqueTempDir());

  // Generate and process 100 DPI image.
  std::vector<std::string> images_100;
  std::vector<uint8_t> bytes_100 = CreateJpg(100, 100);
  images_100.push_back(std::string(bytes_100.begin(), bytes_100.end()));
  auto output_path_100 = temp_dir.GetPath().Append("temp_100.pdf");
  EXPECT_TRUE(ConvertJpgImagesToPdf(images_100, output_path_100,
                                    /*rotate_alternate_pages=*/false,
                                    /*dpi=*/100));
  EXPECT_TRUE(base::PathExists(output_path_100));

  // Generate and process 200 DPI image.
  std::vector<std::string> images_200;
  std::vector<uint8_t> bytes_200 = CreateJpg(200, 200);
  images_200.push_back(std::string(bytes_200.begin(), bytes_200.end()));
  auto output_path_200 = temp_dir.GetPath().Append("temp_200.pdf");
  EXPECT_TRUE(ConvertJpgImagesToPdf(images_200, output_path_200,
                                    /*rotate_alternate_pages=*/false,
                                    /*dpi=*/200));
  EXPECT_TRUE(base::PathExists(output_path_200));

  // Generate and process 300 DPI image.
  std::vector<std::string> images_300;
  std::vector<uint8_t> bytes_300 = CreateJpg(300, 300);
  images_300.push_back(std::string(bytes_300.begin(), bytes_300.end()));
  auto output_path_300 = temp_dir.GetPath().Append("temp_300.pdf");
  EXPECT_TRUE(ConvertJpgImagesToPdf(images_300, output_path_300,
                                    /*rotate_alternate_pages=*/false,
                                    /*dpi=*/300));
  EXPECT_TRUE(base::PathExists(output_path_300));

  // Each file should increase in size as DPI increases.
  int64_t file_size_100;
  int64_t file_size_200;
  int64_t file_size_300;
  EXPECT_TRUE(base::GetFileSize(output_path_100, &file_size_100));
  EXPECT_TRUE(base::GetFileSize(output_path_200, &file_size_200));
  EXPECT_TRUE(base::GetFileSize(output_path_300, &file_size_300));
  EXPECT_GT(file_size_200, file_size_100);
  EXPECT_GT(file_size_300, file_size_200);

  // Verify that the media box is the same size across PDFs.
  const char kMediaBoxString[] = "[0 0 72 72]";
  std::string file_contents;

  EXPECT_TRUE(base::ReadFileToString(output_path_100, &file_contents));
  EXPECT_THAT(file_contents, testing::HasSubstr(kMediaBoxString));

  EXPECT_TRUE(base::ReadFileToString(output_path_200, &file_contents));
  EXPECT_THAT(file_contents, testing::HasSubstr(kMediaBoxString));

  EXPECT_TRUE(base::ReadFileToString(output_path_300, &file_contents));
  EXPECT_THAT(file_contents, testing::HasSubstr(kMediaBoxString));
}

// Test that JPG image can be converted to pdf and saved to vector successfully.
TEST_F(ConvertToPdfTest, ToVector) {
  std::vector<uint8_t> jpg_buffer = CreateJpg(100, 100);
  ASSERT_FALSE(jpg_buffer.empty());

  std::vector<uint8_t> pdf_buffer;
  EXPECT_TRUE(ConvertJpgImageToPdf(jpg_buffer, &pdf_buffer));

  // Smallest PDF should be at least 20 bytes.
  EXPECT_GT(pdf_buffer.size(), 20u);
}

}  // namespace chromeos