17 files changed, 756 insertions, 563 deletions

diff --git a/applypatch/imgdiff.cpp b/applypatch/imgdiff.cpp
index 674cc2b16..415d95f14 100644
--- a/applypatch/imgdiff.cpp
+++ b/applypatch/imgdiff.cpp
@@ -462,12 +462,12 @@ PatchChunk::PatchChunk(const ImageChunk& tgt)
       target_len_(tgt.GetRawDataLength()),
       target_uncompressed_len_(tgt.DataLengthForPatch()),
       target_compress_level_(tgt.GetCompressLevel()),
-      data_(tgt.DataForPatch(), tgt.DataForPatch() + tgt.DataLengthForPatch()) {}
+      data_(tgt.GetRawData(), tgt.GetRawData() + tgt.GetRawDataLength()) {}
 
 // Return true if raw data is smaller than the patch size.
 bool PatchChunk::RawDataIsSmaller(const ImageChunk& tgt, size_t patch_size) {
   size_t target_len = tgt.GetRawDataLength();
-  return (tgt.GetType() == CHUNK_NORMAL && (target_len <= 160 || target_len < patch_size));
+  return target_len < patch_size || (tgt.GetType() == CHUNK_NORMAL && target_len <= 160);
 }
 
 void PatchChunk::UpdateSourceOffset(const SortedRangeSet& src_range) {
diff --git a/applypatch/imgpatch.cpp b/applypatch/imgpatch.cpp
index c4c2707fb..2f8f4851d 100644
--- a/applypatch/imgpatch.cpp
+++ b/applypatch/imgpatch.cpp
@@ -54,6 +54,7 @@ static bool ApplyBSDiffPatchAndStreamOutput(const uint8_t* src_data, size_t src_
                                             const Value& patch, size_t patch_offset,
                                             const char* deflate_header, SinkFn sink) {
   size_t expected_target_length = static_cast<size_t>(Read8(deflate_header + 32));
+  CHECK_GT(expected_target_length, 0);
   int level = Read4(deflate_header + 40);
   int method = Read4(deflate_header + 44);
   int window_bits = Read4(deflate_header + 48);
diff --git a/applypatch/include/applypatch/imgdiff_image.h b/applypatch/include/applypatch/imgdiff_image.h
index 084807237..671605160 100644
--- a/applypatch/include/applypatch/imgdiff_image.h
+++ b/applypatch/include/applypatch/imgdiff_image.h
@@ -44,6 +44,8 @@ class ImageChunk {
   int GetType() const {
     return type_;
   }
+
+  const uint8_t* GetRawData() const;
   size_t GetRawDataLength() const {
     return raw_data_len_;
   }
@@ -99,7 +101,6 @@ class ImageChunk {
                         bsdiff::SuffixArrayIndexInterface** bsdiff_cache);
 
  private:
-  const uint8_t* GetRawData() const;
   bool TryReconstruction(int level);
 
   int type_;                                    // CHUNK_NORMAL, CHUNK_DEFLATE, CHUNK_RAW
diff --git a/bootloader_message/Android.bp b/bootloader_message/Android.bp
index c81c67bdb..ab23733cd 100644
--- a/bootloader_message/Android.bp
+++ b/bootloader_message/Android.bp
@@ -16,6 +16,7 @@
 
 cc_library_static {
     name: "libbootloader_message",
+    recovery_available: true,
     srcs: ["bootloader_message.cpp"],
     cflags: [
         "-Wall",
diff --git a/tests/component/imgdiff_test.cpp b/tests/component/imgdiff_test.cpp
index 6c23def01..cb4868a4a 100644
--- a/tests/component/imgdiff_test.cpp
+++ b/tests/component/imgdiff_test.cpp
@@ -197,12 +197,17 @@ TEST(ImgdiffTest, zip_mode_smoke_store) {
 }
 
 TEST(ImgdiffTest, zip_mode_smoke_compressed) {
+  // Generate 1 block of random data.
+  std::string random_data;
+  random_data.reserve(4096);
+  generate_n(back_inserter(random_data), 4096, []() { return rand() % 256; });
+
   // Construct src and tgt zip files.
   TemporaryFile src_file;
   FILE* src_file_ptr = fdopen(src_file.release(), "wb");
   ZipWriter src_writer(src_file_ptr);
   ASSERT_EQ(0, src_writer.StartEntry("file1.txt", ZipWriter::kCompress));
-  const std::string src_content("abcdefg");
+  const std::string src_content = random_data;
   ASSERT_EQ(0, src_writer.WriteBytes(src_content.data(), src_content.size()));
   ASSERT_EQ(0, src_writer.FinishEntry());
   ASSERT_EQ(0, src_writer.Finish());
@@ -212,7 +217,7 @@ TEST(ImgdiffTest, zip_mode_smoke_compressed) {
   FILE* tgt_file_ptr = fdopen(tgt_file.release(), "wb");
   ZipWriter tgt_writer(tgt_file_ptr);
   ASSERT_EQ(0, tgt_writer.StartEntry("file1.txt", ZipWriter::kCompress));
-  const std::string tgt_content("abcdefgxyz");
+  const std::string tgt_content = random_data + "extra contents";
   ASSERT_EQ(0, tgt_writer.WriteBytes(tgt_content.data(), tgt_content.size()));
   ASSERT_EQ(0, tgt_writer.FinishEntry());
   ASSERT_EQ(0, tgt_writer.Finish());
@@ -245,13 +250,57 @@ TEST(ImgdiffTest, zip_mode_smoke_compressed) {
   verify_patched_image(src, patch, tgt);
 }
 
+TEST(ImgdiffTest, zip_mode_empty_target) {
+  TemporaryFile src_file;
+  FILE* src_file_ptr = fdopen(src_file.release(), "wb");
+  ZipWriter src_writer(src_file_ptr);
+  ASSERT_EQ(0, src_writer.StartEntry("file1.txt", ZipWriter::kCompress));
+  const std::string src_content = "abcdefg";
+  ASSERT_EQ(0, src_writer.WriteBytes(src_content.data(), src_content.size()));
+  ASSERT_EQ(0, src_writer.FinishEntry());
+  ASSERT_EQ(0, src_writer.Finish());
+  ASSERT_EQ(0, fclose(src_file_ptr));
+
+  // Construct a empty entry in the target zip.
+  TemporaryFile tgt_file;
+  FILE* tgt_file_ptr = fdopen(tgt_file.release(), "wb");
+  ZipWriter tgt_writer(tgt_file_ptr);
+  ASSERT_EQ(0, tgt_writer.StartEntry("file1.txt", ZipWriter::kCompress));
+  const std::string tgt_content;
+  ASSERT_EQ(0, tgt_writer.WriteBytes(tgt_content.data(), tgt_content.size()));
+  ASSERT_EQ(0, tgt_writer.FinishEntry());
+  ASSERT_EQ(0, tgt_writer.Finish());
+
+  // Compute patch.
+  TemporaryFile patch_file;
+  std::vector<const char*> args = {
+    "imgdiff", "-z", src_file.path, tgt_file.path, patch_file.path,
+  };
+  ASSERT_EQ(0, imgdiff(args.size(), args.data()));
+
+  // Verify.
+  std::string tgt;
+  ASSERT_TRUE(android::base::ReadFileToString(tgt_file.path, &tgt));
+  std::string src;
+  ASSERT_TRUE(android::base::ReadFileToString(src_file.path, &src));
+  std::string patch;
+  ASSERT_TRUE(android::base::ReadFileToString(patch_file.path, &patch));
+
+  verify_patched_image(src, patch, tgt);
+}
+
 TEST(ImgdiffTest, zip_mode_smoke_trailer_zeros) {
+  // Generate 1 block of random data.
+  std::string random_data;
+  random_data.reserve(4096);
+  generate_n(back_inserter(random_data), 4096, []() { return rand() % 256; });
+
   // Construct src and tgt zip files.
   TemporaryFile src_file;
   FILE* src_file_ptr = fdopen(src_file.release(), "wb");
   ZipWriter src_writer(src_file_ptr);
   ASSERT_EQ(0, src_writer.StartEntry("file1.txt", ZipWriter::kCompress));
-  const std::string src_content("abcdefg");
+  const std::string src_content = random_data;
   ASSERT_EQ(0, src_writer.WriteBytes(src_content.data(), src_content.size()));
   ASSERT_EQ(0, src_writer.FinishEntry());
   ASSERT_EQ(0, src_writer.Finish());
@@ -261,7 +310,7 @@ TEST(ImgdiffTest, zip_mode_smoke_trailer_zeros) {
   FILE* tgt_file_ptr = fdopen(tgt_file.release(), "wb");
   ZipWriter tgt_writer(tgt_file_ptr);
   ASSERT_EQ(0, tgt_writer.StartEntry("file1.txt", ZipWriter::kCompress));
-  const std::string tgt_content("abcdefgxyz");
+  const std::string tgt_content = random_data + "abcdefg";
   ASSERT_EQ(0, tgt_writer.WriteBytes(tgt_content.data(), tgt_content.size()));
   ASSERT_EQ(0, tgt_writer.FinishEntry());
   ASSERT_EQ(0, tgt_writer.Finish());
@@ -298,23 +347,19 @@ TEST(ImgdiffTest, zip_mode_smoke_trailer_zeros) {
 }
 
 TEST(ImgdiffTest, image_mode_simple) {
-  // src: "abcdefgh" + gzipped "xyz" (echo -n "xyz" | gzip -f | hd).
-  const std::vector<char> src_data = { 'a',    'b',    'c',    'd',    'e',    'f',    'g',
-                                       'h',    '\x1f', '\x8b', '\x08', '\x00', '\xc4', '\x1e',
-                                       '\x53', '\x58', '\x00', '\x03', '\xab', '\xa8', '\xac',
-                                       '\x02', '\x00', '\x67', '\xba', '\x8e', '\xeb', '\x03',
-                                       '\x00', '\x00', '\x00' };
-  const std::string src(src_data.cbegin(), src_data.cend());
+  std::string gzipped_source_path = from_testdata_base("gzipped_source");
+  std::string gzipped_source;
+  ASSERT_TRUE(android::base::ReadFileToString(gzipped_source_path, &gzipped_source));
+
+  const std::string src = "abcdefg" + gzipped_source;
   TemporaryFile src_file;
   ASSERT_TRUE(android::base::WriteStringToFile(src, src_file.path));
 
-  // tgt: "abcdefgxyz" + gzipped "xxyyzz".
-  const std::vector<char> tgt_data = {
-    'a',    'b',    'c',    'd',    'e',    'f',    'g',    'x',    'y',    'z',    '\x1f', '\x8b',
-    '\x08', '\x00', '\x62', '\x1f', '\x53', '\x58', '\x00', '\x03', '\xab', '\xa8', '\xa8', '\xac',
-    '\xac', '\xaa', '\x02', '\x00', '\x96', '\x30', '\x06', '\xb7', '\x06', '\x00', '\x00', '\x00'
-  };
-  const std::string tgt(tgt_data.cbegin(), tgt_data.cend());
+  std::string gzipped_target_path = from_testdata_base("gzipped_target");
+  std::string gzipped_target;
+  ASSERT_TRUE(android::base::ReadFileToString(gzipped_target_path, &gzipped_target));
+  const std::string tgt = "abcdefgxyz" + gzipped_target;
+
   TemporaryFile tgt_file;
   ASSERT_TRUE(android::base::WriteStringToFile(tgt, tgt_file.path));
 
@@ -404,23 +449,21 @@ TEST(ImgdiffTest, image_mode_different_num_chunks) {
 }
 
 TEST(ImgdiffTest, image_mode_merge_chunks) {
-  // src: "abcdefgh" + gzipped "xyz" (echo -n "xyz" | gzip -f | hd).
-  const std::vector<char> src_data = { 'a',    'b',    'c',    'd',    'e',    'f',    'g',
-                                       'h',    '\x1f', '\x8b', '\x08', '\x00', '\xc4', '\x1e',
-                                       '\x53', '\x58', '\x00', '\x03', '\xab', '\xa8', '\xac',
-                                       '\x02', '\x00', '\x67', '\xba', '\x8e', '\xeb', '\x03',
-                                       '\x00', '\x00', '\x00' };
-  const std::string src(src_data.cbegin(), src_data.cend());
+  // src: "abcdefg" + gzipped_source.
+  std::string gzipped_source_path = from_testdata_base("gzipped_source");
+  std::string gzipped_source;
+  ASSERT_TRUE(android::base::ReadFileToString(gzipped_source_path, &gzipped_source));
+
+  const std::string src = "abcdefg" + gzipped_source;
   TemporaryFile src_file;
   ASSERT_TRUE(android::base::WriteStringToFile(src, src_file.path));
 
-  // tgt: gzipped "xyz" + "abcdefgh".
-  const std::vector<char> tgt_data = {
-    '\x1f', '\x8b', '\x08', '\x00', '\x62', '\x1f', '\x53', '\x58', '\x00', '\x03', '\xab', '\xa8',
-    '\xa8', '\xac', '\xac', '\xaa', '\x02', '\x00', '\x96', '\x30', '\x06', '\xb7', '\x06', '\x00',
-    '\x00', '\x00', 'a',    'b',    'c',    'd',    'e',    'f',    'g',    'x',    'y',    'z'
-  };
-  const std::string tgt(tgt_data.cbegin(), tgt_data.cend());
+  // tgt: gzipped_target + "abcdefgxyz".
+  std::string gzipped_target_path = from_testdata_base("gzipped_target");
+  std::string gzipped_target;
+  ASSERT_TRUE(android::base::ReadFileToString(gzipped_target_path, &gzipped_target));
+
+  const std::string tgt = gzipped_target + "abcdefgxyz";
   TemporaryFile tgt_file;
   ASSERT_TRUE(android::base::WriteStringToFile(tgt, tgt_file.path));
 
diff --git a/tests/component/updater_test.cpp b/tests/component/updater_test.cpp
index 48363a62b..de8fafd30 100644
--- a/tests/component/updater_test.cpp
+++ b/tests/component/updater_test.cpp
@@ -27,6 +27,8 @@
 #include <vector>
 
 #include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
@@ -48,7 +50,11 @@
 #include "updater/install.h"
 #include "updater/updater.h"
 
-struct selabel_handle *sehandle = nullptr;
+using PackageEntries = std::unordered_map<std::string, std::string>;
+
+static constexpr size_t kTransferListHeaderLines = 4;
+
+struct selabel_handle* sehandle = nullptr;
 
 static void expect(const char* expected, const char* expr_str, CauseCode cause_code,
                    UpdaterInfo* info = nullptr) {
@@ -76,12 +82,12 @@ static void expect(const char* expected, const char* expr_str, CauseCode cause_c
   ASSERT_EQ(cause_code, state.cause_code);
 }
 
-static void BuildUpdatePackage(const std::unordered_map<std::string, std::string>& entries,
-                               int fd) {
+static void BuildUpdatePackage(const PackageEntries& entries, int fd) {
   FILE* zip_file_ptr = fdopen(fd, "wb");
   ZipWriter zip_writer(zip_file_ptr);
 
   for (const auto& entry : entries) {
+    // All the entries are written as STORED.
     ASSERT_EQ(0, zip_writer.StartEntry(entry.first.c_str(), 0));
     if (!entry.second.empty()) {
       ASSERT_EQ(0, zip_writer.WriteBytes(entry.second.data(), entry.second.size()));
@@ -93,6 +99,37 @@ static void BuildUpdatePackage(const std::unordered_map<std::string, std::string
   ASSERT_EQ(0, fclose(zip_file_ptr));
 }
 
+static void RunBlockImageUpdate(bool is_verify, const PackageEntries& entries,
+                                const std::string& image_file, const std::string& result) {
+  CHECK(entries.find("transfer_list") != entries.end());
+
+  // Build the update package.
+  TemporaryFile zip_file;
+  BuildUpdatePackage(entries, zip_file.release());
+
+  MemMapping map;
+  ASSERT_TRUE(map.MapFile(zip_file.path));
+  ZipArchiveHandle handle;
+  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
+
+  // Set up the handler, command_pipe, patch offset & length.
+  UpdaterInfo updater_info;
+  updater_info.package_zip = handle;
+  TemporaryFile temp_pipe;
+  updater_info.cmd_pipe = fdopen(temp_pipe.release(), "wbe");
+  updater_info.package_zip_addr = map.addr;
+  updater_info.package_zip_len = map.length;
+
+  std::string new_data = entries.find("new_data.br") != entries.end() ? "new_data.br" : "new_data";
+  std::string script = is_verify ? "block_image_verify" : "block_image_update";
+  script += R"((")" + image_file + R"(", package_extract_file("transfer_list"), ")" + new_data +
+            R"(", "patch_data"))";
+  expect(result.c_str(), script.c_str(), kNoCause, &updater_info);
+
+  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
+  CloseArchive(handle);
+}
+
 static std::string get_sha1(const std::string& content) {
   uint8_t digest[SHA_DIGEST_LENGTH];
   SHA1(reinterpret_cast<const uint8_t*>(content.c_str()), content.size(), digest);
@@ -101,19 +138,39 @@ static std::string get_sha1(const std::string& content) {
 
 class UpdaterTest : public ::testing::Test {
  protected:
-  virtual void SetUp() override {
+  void SetUp() override {
     RegisterBuiltins();
     RegisterInstallFunctions();
     RegisterBlockImageFunctions();
 
+    // Each test is run in a separate process (isolated mode). Shared temporary files won't cause
+    // conflicts.
     Paths::Get().set_cache_temp_source(temp_saved_source_.path);
     Paths::Get().set_last_command_file(temp_last_command_.path);
     Paths::Get().set_stash_directory_base(temp_stash_base_.path);
+
+    last_command_file_ = temp_last_command_.path;
+    image_file_ = image_temp_file_.path;
+  }
+
+  void TearDown() override {
+    // Clean up the last_command_file if any.
+    ASSERT_TRUE(android::base::RemoveFileIfExists(last_command_file_));
+
+    // Clear partition updated marker if any.
+    std::string updated_marker{ temp_stash_base_.path };
+    updated_marker += "/" + get_sha1(image_temp_file_.path) + ".UPDATED";
+    ASSERT_TRUE(android::base::RemoveFileIfExists(updated_marker));
   }
 
   TemporaryFile temp_saved_source_;
-  TemporaryFile temp_last_command_;
   TemporaryDir temp_stash_base_;
+  std::string last_command_file_;
+  std::string image_file_;
+
+ private:
+  TemporaryFile temp_last_command_;
+  TemporaryFile image_temp_file_;
 };
 
 TEST_F(UpdaterTest, getprop) {
@@ -453,16 +510,18 @@ TEST_F(UpdaterTest, block_image_update_patch_data) {
 
   // Generate the patch data.
   TemporaryFile patch_file;
-  ASSERT_EQ(0, bsdiff::bsdiff(reinterpret_cast<const uint8_t*>(src_content.data()),
-      src_content.size(), reinterpret_cast<const uint8_t*>(tgt_content.data()),
-      tgt_content.size(), patch_file.path, nullptr));
+  ASSERT_EQ(0,
+            bsdiff::bsdiff(reinterpret_cast<const uint8_t*>(src_content.data()), src_content.size(),
+                           reinterpret_cast<const uint8_t*>(tgt_content.data()), tgt_content.size(),
+                           patch_file.path, nullptr));
   std::string patch_content;
   ASSERT_TRUE(android::base::ReadFileToString(patch_file.path, &patch_content));
 
   // Create the transfer list that contains a bsdiff.
   std::string src_hash = get_sha1(src_content);
   std::string tgt_hash = get_sha1(tgt_content);
-  std::vector<std::string> transfer_list = {
+  std::vector<std::string> transfer_list{
+    // clang-format off
     "4",
     "2",
     "0",
@@ -471,183 +530,108 @@ TEST_F(UpdaterTest, block_image_update_patch_data) {
     android::base::StringPrintf("bsdiff 0 %zu %s %s 2,0,2 2 - %s:2,0,2", patch_content.size(),
                                 src_hash.c_str(), tgt_hash.c_str(), src_hash.c_str()),
     "free " + src_hash,
+    // clang-format on
   };
 
-  std::unordered_map<std::string, std::string> entries = {
+  PackageEntries entries{
     { "new_data", "" },
     { "patch_data", patch_content },
     { "transfer_list", android::base::Join(transfer_list, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
+  ASSERT_TRUE(android::base::WriteStringToFile(src_content, image_file_));
 
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
+  RunBlockImageUpdate(false, entries, image_file_, "t");
 
-  // Set up the handler, command_pipe, patch offset & length.
-  UpdaterInfo updater_info;
-  updater_info.package_zip = handle;
-  TemporaryFile temp_pipe;
-  updater_info.cmd_pipe = fdopen(temp_pipe.release(), "wbe");
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
-
-  // Execute the commands in the transfer list.
-  TemporaryFile update_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  std::string script = "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list"), "new_data", "patch_data"))";
-  expect("t", script.c_str(), kNoCause, &updater_info);
   // The update_file should be patched correctly.
   std::string updated_content;
-  ASSERT_TRUE(android::base::ReadFileToString(update_file.path, &updated_content));
-  ASSERT_EQ(tgt_hash, get_sha1(updated_content));
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  ASSERT_TRUE(android::base::ReadFileToString(image_file_, &updated_content));
+  ASSERT_EQ(tgt_content, updated_content);
 }
 
 TEST_F(UpdaterTest, block_image_update_fail) {
   std::string src_content(4096 * 2, 'e');
   std::string src_hash = get_sha1(src_content);
   // Stash and free some blocks, then fail the update intentionally.
-  std::vector<std::string> transfer_list = {
-    "4", "2", "0", "2", "stash " + src_hash + " 2,0,2", "free " + src_hash, "fail",
+  std::vector<std::string> transfer_list{
+    // clang-format off
+    "4",
+    "2",
+    "0",
+    "2",
+    "stash " + src_hash + " 2,0,2",
+    "free " + src_hash,
+    "fail",
+    // clang-format on
   };
 
   // Add a new data of 10 bytes to test the deadlock.
-  std::unordered_map<std::string, std::string> entries = {
+  PackageEntries entries{
     { "new_data", std::string(10, 0) },
     { "patch_data", "" },
     { "transfer_list", android::base::Join(transfer_list, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
+  ASSERT_TRUE(android::base::WriteStringToFile(src_content, image_file_));
 
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
+  RunBlockImageUpdate(false, entries, image_file_, "");
 
-  // Set up the handler, command_pipe, patch offset & length.
-  UpdaterInfo updater_info;
-  updater_info.package_zip = handle;
-  TemporaryFile temp_pipe;
-  updater_info.cmd_pipe = fdopen(temp_pipe.release(), "wbe");
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
-
-  TemporaryFile update_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  // Expect the stashed blocks to be freed.
-  std::string script = "block_image_update(\"" + std::string(update_file.path) +
-                       R"(", package_extract_file("transfer_list"), "new_data", "patch_data"))";
-  expect("", script.c_str(), kNoCause, &updater_info);
   // Updater generates the stash name based on the input file name.
-  std::string name_digest = get_sha1(update_file.path);
+  std::string name_digest = get_sha1(image_file_);
   std::string stash_base = std::string(temp_stash_base_.path) + "/" + name_digest;
   ASSERT_EQ(0, access(stash_base.c_str(), F_OK));
+  // Expect the stashed blocks to be freed.
   ASSERT_EQ(-1, access((stash_base + src_hash).c_str(), F_OK));
   ASSERT_EQ(0, rmdir(stash_base.c_str()));
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
 }
 
 TEST_F(UpdaterTest, new_data_over_write) {
-  std::vector<std::string> transfer_list = {
-    "4", "1", "0", "0", "new 2,0,1",
+  std::vector<std::string> transfer_list{
+    // clang-format off
+    "4",
+    "1",
+    "0",
+    "0",
+    "new 2,0,1",
+    // clang-format on
   };
 
   // Write 4096 + 100 bytes of new data.
-  std::unordered_map<std::string, std::string> entries = {
+  PackageEntries entries{
     { "new_data", std::string(4196, 0) },
     { "patch_data", "" },
     { "transfer_list", android::base::Join(transfer_list, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
-
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
-
-  // Set up the handler, command_pipe, patch offset & length.
-  UpdaterInfo updater_info;
-  updater_info.package_zip = handle;
-  TemporaryFile temp_pipe;
-  updater_info.cmd_pipe = fdopen(temp_pipe.release(), "wbe");
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
-
-  TemporaryFile update_file;
-  std::string script = "block_image_update(\"" + std::string(update_file.path) +
-                       R"(", package_extract_file("transfer_list"), "new_data", "patch_data"))";
-  expect("t", script.c_str(), kNoCause, &updater_info);
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  RunBlockImageUpdate(false, entries, image_file_, "t");
 }
 
 TEST_F(UpdaterTest, new_data_short_write) {
-  std::vector<std::string> transfer_list = {
+  std::vector<std::string> transfer_list{
+    // clang-format off
     "4",
     "1",
     "0",
     "0",
     "new 2,0,1",
+    // clang-format on
   };
 
-  std::unordered_map<std::string, std::string> entries = {
-    { "empty_new_data", "" },
-    { "short_new_data", std::string(10, 'a') },
-    { "exact_new_data", std::string(4096, 'a') },
+  PackageEntries entries{
     { "patch_data", "" },
     { "transfer_list", android::base::Join(transfer_list, '\n') },
   };
 
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
-
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
-
-  // Set up the handler, command_pipe, patch offset & length.
-  UpdaterInfo updater_info;
-  updater_info.package_zip = handle;
-  TemporaryFile temp_pipe;
-  updater_info.cmd_pipe = fdopen(temp_pipe.release(), "wbe");
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
-
   // Updater should report the failure gracefully rather than stuck in deadlock.
-  TemporaryFile update_file;
-  std::string script_empty_data = "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list"), "empty_new_data", "patch_data"))";
-  expect("", script_empty_data.c_str(), kNoCause, &updater_info);
+  entries["new_data"] = "";
+  RunBlockImageUpdate(false, entries, image_file_, "");
 
-  std::string script_short_data = "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list"), "short_new_data", "patch_data"))";
-  expect("", script_short_data.c_str(), kNoCause, &updater_info);
+  entries["new_data"] = std::string(10, 'a');
+  RunBlockImageUpdate(false, entries, image_file_, "");
 
   // Expect to write 1 block of new data successfully.
-  std::string script_exact_data = "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list"), "exact_new_data", "patch_data"))";
-  expect("t", script_exact_data.c_str(), kNoCause, &updater_info);
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  entries["new_data"] = std::string(4096, 'a');
+  RunBlockImageUpdate(false, entries, image_file_, "t");
 }
 
 TEST_F(UpdaterTest, brotli_new_data) {
@@ -680,55 +664,30 @@ TEST_F(UpdaterTest, brotli_new_data) {
     "new 2,99,100",
   };
 
-  std::unordered_map<std::string, std::string> entries = {
-    { "new.dat.br", std::move(encoded_data) },
+  PackageEntries entries{
+    { "new_data.br", std::move(encoded_data) },
     { "patch_data", "" },
     { "transfer_list", android::base::Join(transfer_list, '\n') },
   };
 
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
-
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
-
-  // Set up the handler, command_pipe, patch offset & length.
-  UpdaterInfo updater_info;
-  updater_info.package_zip = handle;
-  TemporaryFile temp_pipe;
-  updater_info.cmd_pipe = fdopen(temp_pipe.release(), "wb");
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
-
-  // Check if we can decompress the new data correctly.
-  TemporaryFile update_file;
-  std::string script_new_data =
-      "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list"), "new.dat.br", "patch_data"))";
-  expect("t", script_new_data.c_str(), kNoCause, &updater_info);
+  RunBlockImageUpdate(false, entries, image_file_, "t");
 
   std::string updated_content;
-  ASSERT_TRUE(android::base::ReadFileToString(update_file.path, &updated_content));
+  ASSERT_TRUE(android::base::ReadFileToString(image_file_, &updated_content));
   ASSERT_EQ(brotli_new_data, updated_content);
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
 }
 
 TEST_F(UpdaterTest, last_command_update) {
-  std::string last_command_file = Paths::Get().last_command_file();
-
-  std::string block1 = std::string(4096, '1');
-  std::string block2 = std::string(4096, '2');
-  std::string block3 = std::string(4096, '3');
+  std::string block1(4096, '1');
+  std::string block2(4096, '2');
+  std::string block3(4096, '3');
   std::string block1_hash = get_sha1(block1);
   std::string block2_hash = get_sha1(block2);
   std::string block3_hash = get_sha1(block3);
 
   // Compose the transfer list to fail the first update.
-  std::vector<std::string> transfer_list_fail = {
+  std::vector<std::string> transfer_list_fail{
+    // clang-format off
     "4",
     "2",
     "0",
@@ -737,10 +696,12 @@ TEST_F(UpdaterTest, last_command_update) {
     "move " + block1_hash + " 2,1,2 1 2,0,1",
     "stash " + block3_hash + " 2,2,3",
     "fail",
+    // clang-format on
   };
 
   // Mimic a resumed update with the same transfer commands.
-  std::vector<std::string> transfer_list_continue = {
+  std::vector<std::string> transfer_list_continue{
+    // clang-format off
     "4",
     "2",
     "0",
@@ -749,127 +710,86 @@ TEST_F(UpdaterTest, last_command_update) {
     "move " + block1_hash + " 2,1,2 1 2,0,1",
     "stash " + block3_hash + " 2,2,3",
     "move " + block1_hash + " 2,2,3 1 2,0,1",
+    // clang-format on
   };
 
-  std::unordered_map<std::string, std::string> entries = {
+  ASSERT_TRUE(android::base::WriteStringToFile(block1 + block2 + block3, image_file_));
+
+  PackageEntries entries{
     { "new_data", "" },
     { "patch_data", "" },
-    { "transfer_list_fail", android::base::Join(transfer_list_fail, '\n') },
-    { "transfer_list_continue", android::base::Join(transfer_list_continue, '\n') },
+    { "transfer_list", android::base::Join(transfer_list_fail, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
+  // "2\nstash " + block3_hash + " 2,2,3"
+  std::string last_command_content = "2\n" + transfer_list_fail[kTransferListHeaderLines + 2];
 
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
-
-  // Set up the handler, command_pipe, patch offset & length.
-  UpdaterInfo updater_info;
-  updater_info.package_zip = handle;
-  TemporaryFile temp_pipe;
-  updater_info.cmd_pipe = fdopen(temp_pipe.release(), "wbe");
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
-
-  std::string src_content = block1 + block2 + block3;
-  TemporaryFile update_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  std::string script =
-      "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list_fail"), "new_data", "patch_data"))";
-  expect("", script.c_str(), kNoCause, &updater_info);
+  RunBlockImageUpdate(false, entries, image_file_, "");
 
   // Expect last_command to contain the last stash command.
-  std::string last_command_content;
-  ASSERT_TRUE(android::base::ReadFileToString(last_command_file.c_str(), &last_command_content));
-  EXPECT_EQ("2\nstash " + block3_hash + " 2,2,3", last_command_content);
+  std::string last_command_actual;
+  ASSERT_TRUE(android::base::ReadFileToString(last_command_file_, &last_command_actual));
+  EXPECT_EQ(last_command_content, last_command_actual);
+
   std::string updated_contents;
-  ASSERT_TRUE(android::base::ReadFileToString(update_file.path, &updated_contents));
+  ASSERT_TRUE(android::base::ReadFileToString(image_file_, &updated_contents));
   ASSERT_EQ(block1 + block1 + block3, updated_contents);
 
-  // Resume the update, expect the first 'move' to be skipped but the second 'move' to be executed.
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  std::string script_second_update =
-      "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list_continue"), "new_data", "patch_data"))";
-  expect("t", script_second_update.c_str(), kNoCause, &updater_info);
-  ASSERT_TRUE(android::base::ReadFileToString(update_file.path, &updated_contents));
-  ASSERT_EQ(block1 + block2 + block1, updated_contents);
+  // "Resume" the update. Expect the first 'move' to be skipped but the second 'move' to be
+  // executed. Note that we intentionally reset the image file.
+  entries["transfer_list"] = android::base::Join(transfer_list_continue, '\n');
+  ASSERT_TRUE(android::base::WriteStringToFile(block1 + block2 + block3, image_file_));
+  RunBlockImageUpdate(false, entries, image_file_, "t");
 
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  ASSERT_TRUE(android::base::ReadFileToString(image_file_, &updated_contents));
+  ASSERT_EQ(block1 + block2 + block1, updated_contents);
 }
 
 TEST_F(UpdaterTest, last_command_update_unresumable) {
-  std::string last_command_file = Paths::Get().last_command_file();
-
-  std::string block1 = std::string(4096, '1');
-  std::string block2 = std::string(4096, '2');
+  std::string block1(4096, '1');
+  std::string block2(4096, '2');
   std::string block1_hash = get_sha1(block1);
   std::string block2_hash = get_sha1(block2);
 
   // Construct an unresumable update with source blocks mismatch.
-  std::vector<std::string> transfer_list_unresumable = {
-    "4", "2", "0", "2", "stash " + block1_hash + " 2,0,1", "move " + block2_hash + " 2,1,2 1 2,0,1",
+  std::vector<std::string> transfer_list_unresumable{
+    // clang-format off
+    "4",
+    "2",
+    "0",
+    "2",
+    "stash " + block1_hash + " 2,0,1",
+    "move " + block2_hash + " 2,1,2 1 2,0,1",
+    // clang-format on
   };
 
-  std::unordered_map<std::string, std::string> entries = {
+  PackageEntries entries{
     { "new_data", "" },
     { "patch_data", "" },
-    { "transfer_list_unresumable", android::base::Join(transfer_list_unresumable, '\n') },
+    { "transfer_list", android::base::Join(transfer_list_unresumable, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
+  ASSERT_TRUE(android::base::WriteStringToFile(block1 + block1, image_file_));
 
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
+  std::string last_command_content = "0\n" + transfer_list_unresumable[kTransferListHeaderLines];
+  ASSERT_TRUE(android::base::WriteStringToFile(last_command_content, last_command_file_));
 
-  // Set up the handler, command_pipe, patch offset & length.
-  UpdaterInfo updater_info;
-  updater_info.package_zip = handle;
-  TemporaryFile temp_pipe;
-  updater_info.cmd_pipe = fdopen(temp_pipe.release(), "wbe");
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
-
-  // Set up the last_command_file
-  ASSERT_TRUE(
-      android::base::WriteStringToFile("0\nstash " + block1_hash + " 2,0,1", last_command_file));
-
-  // The last_command_file will be deleted if the update encounters an unresumable failure
-  // later.
-  std::string src_content = block1 + block1;
-  TemporaryFile update_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  std::string script =
-      "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list_unresumable"), "new_data", "patch_data"))";
-  expect("", script.c_str(), kNoCause, &updater_info);
-  ASSERT_EQ(-1, access(last_command_file.c_str(), R_OK));
+  RunBlockImageUpdate(false, entries, image_file_, "");
 
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  // The last_command_file will be deleted if the update encounters an unresumable failure later.
+  ASSERT_EQ(-1, access(last_command_file_.c_str(), R_OK));
 }
 
 TEST_F(UpdaterTest, last_command_verify) {
-  std::string last_command_file = Paths::Get().last_command_file();
-
-  std::string block1 = std::string(4096, '1');
-  std::string block2 = std::string(4096, '2');
-  std::string block3 = std::string(4096, '3');
+  std::string block1(4096, '1');
+  std::string block2(4096, '2');
+  std::string block3(4096, '3');
   std::string block1_hash = get_sha1(block1);
   std::string block2_hash = get_sha1(block2);
   std::string block3_hash = get_sha1(block3);
 
-  std::vector<std::string> transfer_list_verify = {
+  std::vector<std::string> transfer_list_verify{
+    // clang-format off
     "4",
     "2",
     "0",
@@ -878,55 +798,33 @@ TEST_F(UpdaterTest, last_command_verify) {
     "move " + block1_hash + " 2,0,1 1 2,0,1",
     "move " + block1_hash + " 2,1,2 1 2,0,1",
     "stash " + block3_hash + " 2,2,3",
+    // clang-format on
   };
 
-  std::unordered_map<std::string, std::string> entries = {
+  PackageEntries entries{
     { "new_data", "" },
     { "patch_data", "" },
-    { "transfer_list_verify", android::base::Join(transfer_list_verify, '\n') },
+    { "transfer_list", android::base::Join(transfer_list_verify, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
-
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
-
-  // Set up the handler, command_pipe, patch offset & length.
-  UpdaterInfo updater_info;
-  updater_info.package_zip = handle;
-  TemporaryFile temp_pipe;
-  updater_info.cmd_pipe = fdopen(temp_pipe.release(), "wbe");
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
+  ASSERT_TRUE(android::base::WriteStringToFile(block1 + block1 + block3, image_file_));
 
-  std::string src_content = block1 + block1 + block3;
-  TemporaryFile update_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
+  // Last command: "move " + block1_hash + " 2,1,2 1 2,0,1"
+  std::string last_command_content = "2\n" + transfer_list_verify[kTransferListHeaderLines + 2];
 
-  ASSERT_TRUE(
-      android::base::WriteStringToFile("2\nstash " + block3_hash + " 2,2,3", last_command_file));
+  // First run: expect the verification to succeed and the last_command_file is intact.
+  ASSERT_TRUE(android::base::WriteStringToFile(last_command_content, last_command_file_));
 
-  // Expect the verification to succeed and the last_command_file is intact.
-  std::string script_verify =
-      "block_image_verify(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list_verify"), "new_data","patch_data"))";
-  expect("t", script_verify.c_str(), kNoCause, &updater_info);
+  RunBlockImageUpdate(true, entries, image_file_, "t");
 
-  std::string last_command_content;
-  ASSERT_TRUE(android::base::ReadFileToString(last_command_file.c_str(), &last_command_content));
-  EXPECT_EQ("2\nstash " + block3_hash + " 2,2,3", last_command_content);
+  std::string last_command_actual;
+  ASSERT_TRUE(android::base::ReadFileToString(last_command_file_, &last_command_actual));
+  EXPECT_EQ(last_command_content, last_command_actual);
 
-  // Expect the verification to succeed but last_command_file to be deleted; because the target
-  // blocks don't have the expected contents for the second move command.
-  src_content = block1 + block2 + block3;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  expect("t", script_verify.c_str(), kNoCause, &updater_info);
-  ASSERT_EQ(-1, access(last_command_file.c_str(), R_OK));
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  // Second run with a mismatching block image: expect the verification to succeed but
+  // last_command_file to be deleted; because the target blocks in the last command don't have the
+  // expected contents for the second move command.
+  ASSERT_TRUE(android::base::WriteStringToFile(block1 + block2 + block3, image_file_));
+  RunBlockImageUpdate(true, entries, image_file_, "t");
+  ASSERT_EQ(-1, access(last_command_file_.c_str(), R_OK));
 }
diff --git a/tests/testdata/gzipped_source b/tests/testdata/gzipped_source
new file mode 100644
index 000000000..6d425d059
--- /dev/null
+++ b/tests/testdata/gzipped_source
diff --git a/tests/testdata/gzipped_target b/tests/testdata/gzipped_target
new file mode 100644
index 000000000..562126286
--- /dev/null
+++ b/tests/testdata/gzipped_target
diff --git a/updater_sample/README.md b/updater_sample/README.md
index c68c07caf..3f211ddba 100644
--- a/updater_sample/README.md
+++ b/updater_sample/README.md
@@ -90,9 +90,9 @@ which HTTP headers are supported.
 - [x] Add demo for passing HTTP headers to `UpdateEngine#applyPayload`
 - [x] [Package compatibility check](https://source.android.com/devices/architecture/vintf/match-rules)
 - [x] Deferred switch slot demo
-- [ ] Add tests for `MainActivity`
+- [ ] Add demo for passing NETWORK_ID to `UpdateEngine#applyPayload`
 - [ ] Verify system partition checksum for package
-- [ ] Add non-A/B updates demo
+- [?] Add non-A/B updates demo
 
 
 ## Running tests
diff --git a/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java b/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java
index db99f7c74..1e0fadc27 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java
@@ -279,4 +279,4 @@ public class UpdateConfig implements Parcelable {
 
     }
 
-}
\ No newline at end of file
+}
diff --git a/updater_sample/src/com/example/android/systemupdatersample/UpdateManager.java b/updater_sample/src/com/example/android/systemupdatersample/UpdateManager.java
new file mode 100644
index 000000000..9f0a04e33
--- /dev/null
+++ b/updater_sample/src/com/example/android/systemupdatersample/UpdateManager.java
@@ -0,0 +1,345 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+package com.example.android.systemupdatersample;
+
+import android.content.Context;
+import android.os.UpdateEngine;
+import android.os.UpdateEngineCallback;
+import android.util.Log;
+
+import com.example.android.systemupdatersample.services.PrepareStreamingService;
+import com.example.android.systemupdatersample.util.PayloadSpecs;
+import com.example.android.systemupdatersample.util.UpdateEngineErrorCodes;
+import com.example.android.systemupdatersample.util.UpdateEngineProperties;
+import com.google.common.util.concurrent.AtomicDouble;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.DoubleConsumer;
+import java.util.function.IntConsumer;
+
+/**
+ * Manages the update flow. Asynchronously interacts with the {@link UpdateEngine}.
+ */
+public class UpdateManager {
+
+    private static final String TAG = "UpdateManager";
+
+    /** HTTP Header: User-Agent; it will be sent to the server when streaming the payload. */
+    private static final String HTTP_USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
+            + "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36";
+
+    private final UpdateEngine mUpdateEngine;
+    private final PayloadSpecs mPayloadSpecs;
+
+    private AtomicInteger mUpdateEngineStatus =
+            new AtomicInteger(UpdateEngine.UpdateStatusConstants.IDLE);
+    private AtomicInteger mEngineErrorCode = new AtomicInteger(UpdateEngineErrorCodes.UNKNOWN);
+    private AtomicDouble mProgress = new AtomicDouble(0);
+
+    private final UpdateManager.UpdateEngineCallbackImpl
+            mUpdateEngineCallback = new UpdateManager.UpdateEngineCallbackImpl();
+
+    private PayloadSpec mLastPayloadSpec;
+    private AtomicBoolean mManualSwitchSlotRequired = new AtomicBoolean(true);
+
+    private IntConsumer mOnEngineStatusUpdateCallback = null;
+    private DoubleConsumer mOnProgressUpdateCallback = null;
+    private IntConsumer mOnEngineCompleteCallback = null;
+
+    private final Object mLock = new Object();
+
+    public UpdateManager(UpdateEngine updateEngine, PayloadSpecs payloadSpecs) {
+        this.mUpdateEngine = updateEngine;
+        this.mPayloadSpecs = payloadSpecs;
+    }
+
+    /**
+     * Binds to {@link UpdateEngine}.
+     */
+    public void bind() {
+        this.mUpdateEngine.bind(mUpdateEngineCallback);
+    }
+
+    /**
+     * Unbinds from {@link UpdateEngine}.
+     */
+    public void unbind() {
+        this.mUpdateEngine.unbind();
+    }
+
+    /**
+     * @return a number from {@code 0.0} to {@code 1.0}.
+     */
+    public float getProgress() {
+        return (float) this.mProgress.get();
+    }
+
+    /**
+     * Returns true if manual switching slot is required. Value depends on
+     * the update config {@code ab_config.force_switch_slot}.
+     */
+    public boolean manualSwitchSlotRequired() {
+        return mManualSwitchSlotRequired.get();
+    }
+
+    /**
+     * Sets update engine status update callback. Value of {@code status} will
+     * be one of the values from {@link UpdateEngine.UpdateStatusConstants}.
+     *
+     * @param onStatusUpdateCallback a callback with parameter {@code status}.
+     */
+    public void setOnEngineStatusUpdateCallback(IntConsumer onStatusUpdateCallback) {
+        synchronized (mLock) {
+            this.mOnEngineStatusUpdateCallback = onStatusUpdateCallback;
+        }
+    }
+
+    private Optional<IntConsumer> getOnEngineStatusUpdateCallback() {
+        synchronized (mLock) {
+            return mOnEngineStatusUpdateCallback == null
+                    ? Optional.empty()
+                    : Optional.of(mOnEngineStatusUpdateCallback);
+        }
+    }
+
+    /**
+     * Sets update engine payload application complete callback. Value of {@code errorCode} will
+     * be one of the values from {@link UpdateEngine.ErrorCodeConstants}.
+     *
+     * @param onComplete a callback with parameter {@code errorCode}.
+     */
+    public void setOnEngineCompleteCallback(IntConsumer onComplete) {
+        synchronized (mLock) {
+            this.mOnEngineCompleteCallback = onComplete;
+        }
+    }
+
+    private Optional<IntConsumer> getOnEngineCompleteCallback() {
+        synchronized (mLock) {
+            return mOnEngineCompleteCallback == null
+                    ? Optional.empty()
+                    : Optional.of(mOnEngineCompleteCallback);
+        }
+    }
+
+    /**
+     * Sets progress update callback. Progress is a number from {@code 0.0} to {@code 1.0}.
+     *
+     * @param onProgressCallback a callback with parameter {@code progress}.
+     */
+    public void setOnProgressUpdateCallback(DoubleConsumer onProgressCallback) {
+        synchronized (mLock) {
+            this.mOnProgressUpdateCallback = onProgressCallback;
+        }
+    }
+
+    private Optional<DoubleConsumer> getOnProgressUpdateCallback() {
+        synchronized (mLock) {
+            return mOnProgressUpdateCallback == null
+                    ? Optional.empty()
+                    : Optional.of(mOnProgressUpdateCallback);
+        }
+    }
+
+    /**
+     * Requests update engine to stop any ongoing update. If an update has been applied,
+     * leave it as is.
+     *
+     * <p>Sometimes it's possible that the
+     * update engine would throw an error when the method is called, and the only way to
+     * handle it is to catch the exception.</p>
+     */
+    public void cancelRunningUpdate() {
+        try {
+            mUpdateEngine.cancel();
+        } catch (Exception e) {
+            Log.w(TAG, "UpdateEngine failed to stop the ongoing update", e);
+        }
+    }
+
+    /**
+     * Resets update engine to IDLE state. If an update has been applied it reverts it.
+     *
+     * <p>Sometimes it's possible that the
+     * update engine would throw an error when the method is called, and the only way to
+     * handle it is to catch the exception.</p>
+     */
+    public void resetUpdate() {
+        try {
+            mUpdateEngine.resetStatus();
+        } catch (Exception e) {
+            Log.w(TAG, "UpdateEngine failed to reset the update", e);
+        }
+    }
+
+    /**
+     * Applies the given update.
+     *
+     * <p>UpdateEngine works asynchronously. This method doesn't wait until
+     * end of the update.</p>
+     */
+    public void applyUpdate(Context context, UpdateConfig config) {
+        mEngineErrorCode.set(UpdateEngineErrorCodes.UNKNOWN);
+
+        if (!config.getAbConfig().getForceSwitchSlot()) {
+            mManualSwitchSlotRequired.set(true);
+        } else {
+            mManualSwitchSlotRequired.set(false);
+        }
+
+        if (config.getInstallType() == UpdateConfig.AB_INSTALL_TYPE_NON_STREAMING) {
+            applyAbNonStreamingUpdate(config);
+        } else {
+            applyAbStreamingUpdate(context, config);
+        }
+    }
+
+    private void applyAbNonStreamingUpdate(UpdateConfig config) {
+        List<String> extraProperties = prepareExtraProperties(config);
+
+        PayloadSpec payload;
+        try {
+            payload = mPayloadSpecs.forNonStreaming(config.getUpdatePackageFile());
+        } catch (IOException e) {
+            Log.e(TAG, "Error creating payload spec", e);
+            return;
+        }
+        updateEngineApplyPayload(payload, extraProperties);
+    }
+
+    private void applyAbStreamingUpdate(Context context, UpdateConfig config) {
+        List<String> extraProperties = prepareExtraProperties(config);
+
+        Log.d(TAG, "Starting PrepareStreamingService");
+        PrepareStreamingService.startService(context, config, (code, payloadSpec) -> {
+            if (code == PrepareStreamingService.RESULT_CODE_SUCCESS) {
+                extraProperties.add("USER_AGENT=" + HTTP_USER_AGENT);
+                config.getStreamingMetadata()
+                        .getAuthorization()
+                        .ifPresent(s -> extraProperties.add("AUTHORIZATION=" + s));
+                updateEngineApplyPayload(payloadSpec, extraProperties);
+            } else {
+                Log.e(TAG, "PrepareStreamingService failed, result code is " + code);
+            }
+        });
+    }
+
+    private List<String> prepareExtraProperties(UpdateConfig config) {
+        List<String> extraProperties = new ArrayList<>();
+
+        if (!config.getAbConfig().getForceSwitchSlot()) {
+            // Disable switch slot on reboot, which is enabled by default.
+            // User will enable it manually by clicking "Switch Slot" button on the screen.
+            extraProperties.add(UpdateEngineProperties.PROPERTY_DISABLE_SWITCH_SLOT_ON_REBOOT);
+        }
+        return extraProperties;
+    }
+
+    /**
+     * Applies given payload.
+     *
+     * <p>UpdateEngine works asynchronously. This method doesn't wait until
+     * end of the update.</p>
+     *
+     * <p>It's possible that the update engine throws a generic error, such as upon seeing invalid
+     * payload properties (which come from OTA packages), or failing to set up the network
+     * with the given id.</p>
+     *
+     * @param payloadSpec contains url, offset and size to {@code PAYLOAD_BINARY_FILE_NAME}
+     * @param extraProperties additional properties to pass to {@link UpdateEngine#applyPayload}
+     */
+    private void updateEngineApplyPayload(PayloadSpec payloadSpec, List<String> extraProperties) {
+        mLastPayloadSpec = payloadSpec;
+
+        ArrayList<String> properties = new ArrayList<>(payloadSpec.getProperties());
+        if (extraProperties != null) {
+            properties.addAll(extraProperties);
+        }
+        try {
+            mUpdateEngine.applyPayload(
+                    payloadSpec.getUrl(),
+                    payloadSpec.getOffset(),
+                    payloadSpec.getSize(),
+                    properties.toArray(new String[0]));
+        } catch (Exception e) {
+            Log.e(TAG, "UpdateEngine failed to apply the update", e);
+        }
+    }
+
+    /**
+     * Sets the new slot that has the updated partitions as the active slot,
+     * which device will boot into next time.
+     * This method is only supposed to be called after the payload is applied.
+     *
+     * Invoking {@link UpdateEngine#applyPayload} with the same payload url, offset, size
+     * and payload metadata headers doesn't trigger new update. It can be used to just switch
+     * active A/B slot.
+     *
+     * {@link UpdateEngine#applyPayload} might take several seconds to finish, and it will
+     * invoke callbacks {@link this#onStatusUpdate} and {@link this#onPayloadApplicationComplete)}.
+     */
+    public void setSwitchSlotOnReboot() {
+        Log.d(TAG, "setSwitchSlotOnReboot invoked");
+        List<String> extraProperties = new ArrayList<>();
+        // PROPERTY_SKIP_POST_INSTALL should be passed on to skip post-installation hooks.
+        extraProperties.add(UpdateEngineProperties.PROPERTY_SKIP_POST_INSTALL);
+        // It sets property SWITCH_SLOT_ON_REBOOT=1 by default.
+        // HTTP headers are not required, UpdateEngine is not expected to stream payload.
+        updateEngineApplyPayload(mLastPayloadSpec, extraProperties);
+    }
+
+    private void onStatusUpdate(int status, float progress) {
+        int previousStatus = mUpdateEngineStatus.get();
+        mUpdateEngineStatus.set(status);
+        mProgress.set(progress);
+
+        getOnProgressUpdateCallback().ifPresent(callback -> callback.accept(progress));
+
+        if (previousStatus != status) {
+            getOnEngineStatusUpdateCallback().ifPresent(callback -> callback.accept(status));
+        }
+    }
+
+    private void onPayloadApplicationComplete(int errorCode) {
+        Log.d(TAG, "onPayloadApplicationComplete invoked, errorCode=" + errorCode);
+        mEngineErrorCode.set(errorCode);
+
+        getOnEngineCompleteCallback()
+                .ifPresent(callback -> callback.accept(errorCode));
+    }
+
+    /**
+     * Helper class to delegate {@code update_engine} callbacks to UpdateManager
+     */
+    class UpdateEngineCallbackImpl extends UpdateEngineCallback {
+        @Override
+        public void onStatusUpdate(int status, float percent) {
+            UpdateManager.this.onStatusUpdate(status, percent);
+        }
+
+        @Override
+        public void onPayloadApplicationComplete(int errorCode) {
+            UpdateManager.this.onPayloadApplicationComplete(errorCode);
+        }
+    }
+
+}
diff --git a/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java b/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
index 9bab1319d..9237bc794 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
@@ -22,7 +22,6 @@ import android.graphics.Color;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.UpdateEngine;
-import android.os.UpdateEngineCallback;
 import android.util.Log;
 import android.view.View;
 import android.widget.ArrayAdapter;
@@ -32,21 +31,15 @@ import android.widget.Spinner;
 import android.widget.TextView;
 import android.widget.Toast;
 
-import com.example.android.systemupdatersample.PayloadSpec;
 import com.example.android.systemupdatersample.R;
 import com.example.android.systemupdatersample.UpdateConfig;
-import com.example.android.systemupdatersample.services.PrepareStreamingService;
+import com.example.android.systemupdatersample.UpdateManager;
 import com.example.android.systemupdatersample.util.PayloadSpecs;
 import com.example.android.systemupdatersample.util.UpdateConfigs;
 import com.example.android.systemupdatersample.util.UpdateEngineErrorCodes;
-import com.example.android.systemupdatersample.util.UpdateEngineProperties;
 import com.example.android.systemupdatersample.util.UpdateEngineStatuses;
 
-import java.io.IOException;
-import java.util.ArrayList;
 import java.util.List;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * UI for SystemUpdaterSample app.
@@ -55,10 +48,6 @@ public class MainActivity extends Activity {
 
     private static final String TAG = "MainActivity";
 
-    /** HTTP Header: User-Agent; it will be sent to the server when streaming the payload. */
-    private static final String HTTP_USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
-            + "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36";
-
     private TextView mTextViewBuild;
     private Spinner mSpinnerConfigs;
     private TextView mTextViewConfigsDirHint;
@@ -73,18 +62,9 @@ public class MainActivity extends Activity {
     private Button mButtonSwitchSlot;
 
     private List<UpdateConfig> mConfigs;
-    private AtomicInteger mUpdateEngineStatus =
-            new AtomicInteger(UpdateEngine.UpdateStatusConstants.IDLE);
-    private PayloadSpec mLastPayloadSpec;
-    private AtomicBoolean mManualSwitchSlotRequired = new AtomicBoolean(true);
-    private final PayloadSpecs mPayloadSpecs = new PayloadSpecs();
-
-    /**
-     * Listen to {@code update_engine} events.
-     */
-    private UpdateEngineCallbackImpl mUpdateEngineCallback = new UpdateEngineCallbackImpl();
 
-    private final UpdateEngine mUpdateEngine = new UpdateEngine();
+    private final UpdateManager mUpdateManager =
+            new UpdateManager(new UpdateEngine(), new PayloadSpecs());
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -109,15 +89,31 @@ public class MainActivity extends Activity {
         uiReset();
         loadUpdateConfigs();
 
-        this.mUpdateEngine.bind(mUpdateEngineCallback);
+        this.mUpdateManager.setOnEngineStatusUpdateCallback(this::onStatusUpdate);
+        this.mUpdateManager.setOnProgressUpdateCallback(this::onProgressUpdate);
+        this.mUpdateManager.setOnEngineCompleteCallback(this::onPayloadApplicationComplete);
     }
 
     @Override
     protected void onDestroy() {
-        this.mUpdateEngine.unbind();
+        this.mUpdateManager.setOnEngineStatusUpdateCallback(null);
+        this.mUpdateManager.setOnProgressUpdateCallback(null);
+        this.mUpdateManager.setOnEngineCompleteCallback(null);
         super.onDestroy();
     }
 
+    @Override
+    protected void onResume() {
+        super.onResume();
+        this.mUpdateManager.bind();
+    }
+
+    @Override
+    protected void onPause() {
+        this.mUpdateManager.unbind();
+        super.onPause();
+    }
+
     /**
      * reload button is clicked
      */
@@ -147,7 +143,7 @@ public class MainActivity extends Activity {
                 .setIcon(android.R.drawable.ic_dialog_alert)
                 .setPositiveButton(android.R.string.ok, (dialog, whichButton) -> {
                     uiSetUpdating();
-                    applyUpdate(getSelectedConfig());
+                    mUpdateManager.applyUpdate(this, getSelectedConfig());
                 })
                 .setNegativeButton(android.R.string.cancel, null)
                 .show();
@@ -162,7 +158,7 @@ public class MainActivity extends Activity {
                 .setMessage("Do you really want to cancel running update?")
                 .setIcon(android.R.drawable.ic_dialog_alert)
                 .setPositiveButton(android.R.string.ok, (dialog, whichButton) -> {
-                    stopRunningUpdate();
+                    mUpdateManager.cancelRunningUpdate();
                 })
                 .setNegativeButton(android.R.string.cancel, null).show();
     }
@@ -177,7 +173,7 @@ public class MainActivity extends Activity {
                         + " and restore old version?")
                 .setIcon(android.R.drawable.ic_dialog_alert)
                 .setPositiveButton(android.R.string.ok, (dialog, whichButton) -> {
-                    resetUpdate();
+                    mUpdateManager.resetUpdate();
                 })
                 .setNegativeButton(android.R.string.cancel, null).show();
     }
@@ -186,7 +182,7 @@ public class MainActivity extends Activity {
      * switch slot button clicked
      */
     public void onSwitchSlotClick(View view) {
-        setSwitchSlotOnReboot();
+        mUpdateManager.setSwitchSlotOnReboot();
     }
 
     /**
@@ -194,26 +190,26 @@ public class MainActivity extends Activity {
      * be one of the values from {@link UpdateEngine.UpdateStatusConstants},
      * and {@code percent} will be from {@code 0.0} to {@code 1.0}.
      */
-    private void onStatusUpdate(int status, float percent) {
-        mProgressBar.setProgress((int) (100 * percent));
-        if (mUpdateEngineStatus.get() != status) {
-            mUpdateEngineStatus.set(status);
-            runOnUiThread(() -> {
-                Log.e("UpdateEngine", "StatusUpdate - status="
-                        + UpdateEngineStatuses.getStatusText(status)
-                        + "/" + status);
-                Toast.makeText(this, "Update Status changed", Toast.LENGTH_LONG)
-                        .show();
-                if (status == UpdateEngine.UpdateStatusConstants.IDLE) {
-                    Log.d(TAG, "status changed, resetting ui");
-                    uiReset();
-                } else {
-                    Log.d(TAG, "status changed, setting ui to updating mode");
-                    uiSetUpdating();
-                }
-                setUiStatus(status);
-            });
-        }
+    private void onStatusUpdate(int status) {
+        runOnUiThread(() -> {
+            Log.e("UpdateEngine", "StatusUpdate - status="
+                    + UpdateEngineStatuses.getStatusText(status)
+                    + "/" + status);
+            Toast.makeText(this, "Update Status changed", Toast.LENGTH_LONG)
+                    .show();
+            if (status == UpdateEngine.UpdateStatusConstants.IDLE) {
+                Log.d(TAG, "status changed, resetting ui");
+                uiReset();
+            } else {
+                Log.d(TAG, "status changed, setting ui to updating mode");
+                uiSetUpdating();
+            }
+            setUiStatus(status);
+        });
+    }
+
+    private void onProgressUpdate(double progress) {
+        mProgressBar.setProgress((int) (100 * progress));
     }
 
     /**
@@ -234,7 +230,7 @@ public class MainActivity extends Activity {
             setUiCompletion(errorCode);
             if (errorCode == UpdateEngineErrorCodes.UPDATED_BUT_NOT_ACTIVE) {
                 // if update was successfully applied.
-                if (mManualSwitchSlotRequired.get()) {
+                if (mUpdateManager.manualSwitchSlotRequired()) {
                     // Show "Switch Slot" button.
                     uiShowSwitchSlotInfo();
                 }
@@ -321,143 +317,4 @@ public class MainActivity extends Activity {
         return mConfigs.get(mSpinnerConfigs.getSelectedItemPosition());
     }
 
-    /**
-     * Applies the given update
-     */
-    private void applyUpdate(final UpdateConfig config) {
-        List<String> extraProperties = new ArrayList<>();
-
-        if (!config.getAbConfig().getForceSwitchSlot()) {
-            // Disable switch slot on reboot, which is enabled by default.
-            // User will enable it manually by clicking "Switch Slot" button on the screen.
-            extraProperties.add(UpdateEngineProperties.PROPERTY_DISABLE_SWITCH_SLOT_ON_REBOOT);
-            mManualSwitchSlotRequired.set(true);
-        } else {
-            mManualSwitchSlotRequired.set(false);
-        }
-
-        if (config.getInstallType() == UpdateConfig.AB_INSTALL_TYPE_NON_STREAMING) {
-            PayloadSpec payload;
-            try {
-                payload = mPayloadSpecs.forNonStreaming(config.getUpdatePackageFile());
-            } catch (IOException e) {
-                Log.e(TAG, "Error creating payload spec", e);
-                Toast.makeText(this, "Error creating payload spec", Toast.LENGTH_LONG)
-                        .show();
-                return;
-            }
-            updateEngineApplyPayload(payload, extraProperties);
-        } else {
-            Log.d(TAG, "Starting PrepareStreamingService");
-            PrepareStreamingService.startService(this, config, (code, payloadSpec) -> {
-                if (code == PrepareStreamingService.RESULT_CODE_SUCCESS) {
-                    extraProperties.add("USER_AGENT=" + HTTP_USER_AGENT);
-                    config.getStreamingMetadata()
-                            .getAuthorization()
-                            .ifPresent(s -> extraProperties.add("AUTHORIZATION=" + s));
-                    updateEngineApplyPayload(payloadSpec, extraProperties);
-                } else {
-                    Log.e(TAG, "PrepareStreamingService failed, result code is " + code);
-                    Toast.makeText(
-                            MainActivity.this,
-                            "PrepareStreamingService failed, result code is " + code,
-                            Toast.LENGTH_LONG).show();
-                }
-            });
-        }
-    }
-
-    /**
-     * Applies given payload.
-     *
-     * UpdateEngine works asynchronously. This method doesn't wait until
-     * end of the update.
-     *
-     * @param payloadSpec contains url, offset and size to {@code PAYLOAD_BINARY_FILE_NAME}
-     * @param extraProperties additional properties to pass to {@link UpdateEngine#applyPayload}
-     */
-    private void updateEngineApplyPayload(PayloadSpec payloadSpec, List<String> extraProperties) {
-        mLastPayloadSpec = payloadSpec;
-
-        ArrayList<String> properties = new ArrayList<>(payloadSpec.getProperties());
-        if (extraProperties != null) {
-            properties.addAll(extraProperties);
-        }
-        try {
-            mUpdateEngine.applyPayload(
-                    payloadSpec.getUrl(),
-                    payloadSpec.getOffset(),
-                    payloadSpec.getSize(),
-                    properties.toArray(new String[0]));
-        } catch (Exception e) {
-            Log.e(TAG, "UpdateEngine failed to apply the update", e);
-            Toast.makeText(
-                    this,
-                    "UpdateEngine failed to apply the update",
-                    Toast.LENGTH_LONG).show();
-        }
-    }
-
-    /**
-     * Sets the new slot that has the updated partitions as the active slot,
-     * which device will boot into next time.
-     * This method is only supposed to be called after the payload is applied.
-     *
-     * Invoking {@link UpdateEngine#applyPayload} with the same payload url, offset, size
-     * and payload metadata headers doesn't trigger new update. It can be used to just switch
-     * active A/B slot.
-     *
-     * {@link UpdateEngine#applyPayload} might take several seconds to finish, and it will
-     * invoke callbacks {@link this#onStatusUpdate} and {@link this#onPayloadApplicationComplete)}.
-     */
-    private void setSwitchSlotOnReboot() {
-        Log.d(TAG, "setSwitchSlotOnReboot invoked");
-        List<String> extraProperties = new ArrayList<>();
-        // PROPERTY_SKIP_POST_INSTALL should be passed on to skip post-installation hooks.
-        extraProperties.add(UpdateEngineProperties.PROPERTY_SKIP_POST_INSTALL);
-        // It sets property SWITCH_SLOT_ON_REBOOT=1 by default.
-        // HTTP headers are not required, UpdateEngine is not expected to stream payload.
-        updateEngineApplyPayload(mLastPayloadSpec, extraProperties);
-        uiHideSwitchSlotInfo();
-    }
-
-    /**
-     * Requests update engine to stop any ongoing update. If an update has been applied,
-     * leave it as is.
-     */
-    private void stopRunningUpdate() {
-        try {
-            mUpdateEngine.cancel();
-        } catch (Exception e) {
-            Log.w(TAG, "UpdateEngine failed to stop the ongoing update", e);
-        }
-    }
-
-    /**
-     * Resets update engine to IDLE state. Requests to cancel any onging update, or to revert if an
-     * update has been applied.
-     */
-    private void resetUpdate() {
-        try {
-            mUpdateEngine.resetStatus();
-        } catch (Exception e) {
-            Log.w(TAG, "UpdateEngine failed to reset the update", e);
-        }
-    }
-
-    /**
-     * Helper class to delegate {@code update_engine} callbacks to MainActivity
-     */
-    class UpdateEngineCallbackImpl extends UpdateEngineCallback {
-        @Override
-        public void onStatusUpdate(int status, float percent) {
-            MainActivity.this.onStatusUpdate(status, percent);
-        }
-
-        @Override
-        public void onPayloadApplicationComplete(int errorCode) {
-            MainActivity.this.onPayloadApplicationComplete(errorCode);
-        }
-    }
-
 }
diff --git a/updater_sample/src/com/example/android/systemupdatersample/util/PayloadSpecs.java b/updater_sample/src/com/example/android/systemupdatersample/util/PayloadSpecs.java
index b98b97c37..f06231726 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/util/PayloadSpecs.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/util/PayloadSpecs.java
@@ -32,7 +32,9 @@ import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 
 /** The helper class that creates {@link PayloadSpec}. */
-public final class PayloadSpecs {
+public class PayloadSpecs {
+
+    public PayloadSpecs() {}
 
     /**
      * The payload PAYLOAD_ENTRY is stored in the zip package to comply with the Android OTA package
diff --git a/updater_sample/src/com/example/android/systemupdatersample/util/UpdateEngineErrorCodes.java b/updater_sample/src/com/example/android/systemupdatersample/util/UpdateEngineErrorCodes.java
index 6d319c5af..f06ddf7fc 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/util/UpdateEngineErrorCodes.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/util/UpdateEngineErrorCodes.java
@@ -34,6 +34,7 @@ public final class UpdateEngineErrorCodes {
     * Error code from the update engine. Values must agree with the ones in
     * system/update_engine/common/error_code.h.
     */
+    public static final int UNKNOWN = -1;
     public static final int UPDATED_BUT_NOT_ACTIVE = 52;
 
     private static final SparseArray<String> CODE_TO_NAME_MAP = new SparseArray<>();
diff --git a/updater_sample/tests/Android.mk b/updater_sample/tests/Android.mk
index a1a4664dc..9aec372e3 100644
--- a/updater_sample/tests/Android.mk
+++ b/updater_sample/tests/Android.mk
@@ -23,9 +23,9 @@ LOCAL_MODULE_TAGS := tests
 LOCAL_JAVA_LIBRARIES := \
     android.test.base.stubs \
     android.test.runner.stubs \
-    guava \
+    guava
+LOCAL_STATIC_JAVA_LIBRARIES := android-support-test \
     mockito-target-minus-junit4
-LOCAL_STATIC_JAVA_LIBRARIES := android-support-test
 LOCAL_INSTRUMENTATION_FOR := SystemUpdaterSample
 LOCAL_PROGUARD_ENABLED := disabled
 
diff --git a/updater_sample/tests/src/com/example/android/systemupdatersample/UpdateManagerTest.java b/updater_sample/tests/src/com/example/android/systemupdatersample/UpdateManagerTest.java
new file mode 100644
index 000000000..0657a5eb6
--- /dev/null
+++ b/updater_sample/tests/src/com/example/android/systemupdatersample/UpdateManagerTest.java
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+package com.example.android.systemupdatersample;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.os.UpdateEngine;
+import android.os.UpdateEngineCallback;
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
+
+import com.example.android.systemupdatersample.util.PayloadSpecs;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+
+import java.util.function.IntConsumer;
+
+/**
+ * Tests for {@link UpdateManager}
+ */
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class UpdateManagerTest {
+
+    @Rule
+    public MockitoRule mockito = MockitoJUnit.rule();
+
+    @Mock
+    private UpdateEngine mUpdateEngine;
+    @Mock
+    private PayloadSpecs mPayloadSpecs;
+    private UpdateManager mUpdateManager;
+
+    @Before
+    public void setUp() {
+        mUpdateManager = new UpdateManager(mUpdateEngine, mPayloadSpecs);
+    }
+
+    @Test
+    public void storesProgressThenInvokesCallbacks() {
+        IntConsumer statusUpdateCallback = mock(IntConsumer.class);
+
+        // When UpdateManager is bound to update_engine, it passes
+        // UpdateManager.UpdateEngineCallbackImpl as a callback to update_engine.
+        when(mUpdateEngine.bind(any(UpdateEngineCallback.class))).thenAnswer(answer -> {
+            UpdateEngineCallback callback = answer.getArgument(0);
+            callback.onStatusUpdate(/*engineStatus*/ 4, /*engineProgress*/ 0.2f);
+            return null;
+        });
+
+        mUpdateManager.setOnEngineStatusUpdateCallback(statusUpdateCallback);
+
+        // Making sure that manager.getProgress() returns correct progress
+        // in "onEngineStatusUpdate" callback.
+        doAnswer(answer -> {
+            assertEquals(0.2f, mUpdateManager.getProgress(), 1E-5);
+            return null;
+        }).when(statusUpdateCallback).accept(anyInt());
+
+        mUpdateManager.bind();
+
+        verify(statusUpdateCallback, times(1)).accept(4);
+    }
+
+}
diff --git a/updater_sample/tests/src/com/example/android/systemupdatersample/ui/MainActivityTest.java b/updater_sample/tests/src/com/example/android/systemupdatersample/ui/MainActivityTest.java
deleted file mode 100644
index 01014168a..000000000
--- a/updater_sample/tests/src/com/example/android/systemupdatersample/ui/MainActivityTest.java
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
- * Copyright (C) 2018 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.
- */
-
-package com.example.android.systemupdatersample.ui;
-
-import static org.junit.Assert.assertNotNull;
-
-import android.support.test.filters.MediumTest;
-import android.support.test.rule.ActivityTestRule;
-import android.support.test.runner.AndroidJUnit4;
-
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-/**
- * Make sure that the main launcher activity opens up properly, which will be
- * verified by {@link #activityLaunches}.
- */
-@RunWith(AndroidJUnit4.class)
-@MediumTest
-public class MainActivityTest {
-
-    @Rule
-    public final ActivityTestRule<MainActivity> mActivityRule =
-            new ActivityTestRule<>(MainActivity.class);
-
-    /**
-     * Verifies that the activity under test can be launched.
-     */
-    @Test
-    public void activityLaunches() {
-        assertNotNull(mActivityRule.getActivity());
-    }
-}