diff --git a/test_installer_main.cc b/test_installer_main.cc
new file mode 100644
index 0000000..96e257d
--- /dev/null
+++ b/test_installer_main.cc
@@ -0,0 +1,200 @@
+// Copyright (c) 2009 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 <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <set>
+#include <string>
+#include <vector>
+
+#include <gflags/gflags.h>
+#include <glib.h>
+#include "chromeos/obsolete_logging.h"
+
+#include "update_engine/delta_diff_generator.h"
+#include "update_engine/delta_diff_parser.h"
+#include "update_engine/filesystem_copier_action.h"
+#include "update_engine/install_action.h"
+#include "update_engine/install_plan.h"
+#include "update_engine/test_utils.h"
+#include "update_engine/update_metadata.pb.h"
+#include "update_engine/utils.h"
+
+// This file contains a simple program that unpacks a delta diff into a
+// directory.
+
+using std::set;
+using std::string;
+using std::vector;
+using std::tr1::shared_ptr;
+
+DEFINE_string(delta, "", "the delta file");
+DEFINE_string(output_dev, "", "the output device");
+DEFINE_string(root, "", "the fake system root");
+DEFINE_string(dump_delta, "", "path to delta file to dump");
+
+namespace chromeos_update_engine {
+
+class TestInstaller : public ActionProcessorDelegate {
+ public:
+  TestInstaller(GMainLoop *loop,
+                const string& sys_root,
+                const string& delta_path,
+                const string& install_path)
+      : loop_(loop),
+        sys_root_(sys_root),
+        delta_path_(delta_path),
+        install_path_(install_path) {}
+  void Update();
+
+  // Delegate method:
+  void ProcessingDone(const ActionProcessor* processor, bool success);
+ private:
+  vector<shared_ptr<AbstractAction> > actions_;
+  ActionProcessor processor_;
+  GMainLoop *loop_;
+  string sys_root_;
+  string delta_path_;
+  string install_path_;
+};
+
+// Returns true on success. If there was no update available, that's still
+// success.
+// If force_full is true, try to force a full update.
+void TestInstaller::Update() {
+  CHECK(!processor_.IsRunning());
+  processor_.set_delegate(this);
+
+  // Actions:
+  shared_ptr<ObjectFeederAction<InstallPlan> > object_feeder_action(
+      new ObjectFeederAction<InstallPlan>);
+  shared_ptr<FilesystemCopierAction> filesystem_copier_action(
+      new FilesystemCopierAction);
+  shared_ptr<InstallAction> install_action(
+      new InstallAction);
+
+  actions_.push_back(object_feeder_action);
+  actions_.push_back(filesystem_copier_action);
+  actions_.push_back(install_action);
+
+  // Enqueue the actions
+  for (vector<shared_ptr<AbstractAction> >::iterator it = actions_.begin();
+       it != actions_.end(); ++it) {
+    processor_.EnqueueAction(it->get());
+  }
+
+  // Bond them together. We have to use the leaf-types when calling
+  // BondActions().
+  BondActions(object_feeder_action.get(), filesystem_copier_action.get());
+  BondActions(filesystem_copier_action.get(), install_action.get());
+  
+  InstallPlan install_plan(false,
+                           "",
+                           "",
+                           delta_path_,
+                           install_path_);
+  filesystem_copier_action->set_copy_source(sys_root_);
+  object_feeder_action->set_obj(install_plan);
+  processor_.StartProcessing();
+}
+
+void TestInstaller::ProcessingDone(const ActionProcessor* processor,
+                                   bool success) {
+  LOG(INFO) << "install " << (success ? "succeeded" : "failed");
+  actions_.clear();
+  g_main_loop_quit(loop_);
+}
+
+gboolean TestInstallInMainLoop(void* arg) {
+  TestInstaller* test_installer = reinterpret_cast<TestInstaller*>(arg);
+  test_installer->Update();
+  return FALSE;  // Don't call this callback function again
+}
+
+
+void usage(const char* argv0) {
+  printf("usage: %s --root=system_root --delta=delta_file "
+         "--output_dev=output_dev\n", argv0);
+  exit(1);
+}
+
+bool Main(int argc, char** argv) {
+  g_thread_init(NULL);
+  google::ParseCommandLineFlags(&argc, &argv, true);
+  logging::InitLogging("",
+                       logging::LOG_ONLY_TO_SYSTEM_DEBUG_LOG,
+                       logging::DONT_LOCK_LOG_FILE,
+                       logging::APPEND_TO_OLD_LOG_FILE);
+
+  LOG(INFO) << "starting";
+  
+  if (!FLAGS_dump_delta.empty()) {
+    CHECK(FLAGS_delta.empty());
+    CHECK(FLAGS_root.empty());
+    CHECK(FLAGS_output_dev.empty());
+    
+    DeltaDiffParser parser(FLAGS_dump_delta);
+    for (DeltaDiffParser::Iterator it = parser.Begin();
+         it != parser.End(); it.Increment()) {
+      DeltaArchiveManifest_File file = it.GetFile();
+      const char* format = "---";
+      ssize_t offset = -1;
+      ssize_t length = -1;
+      if (file.has_data_format()) {
+        switch (file.data_format()) {
+          case DeltaArchiveManifest_File_DataFormat_FULL:
+          format = "FULL";
+          break;
+          case DeltaArchiveManifest_File_DataFormat_FULL_GZ:
+          format = "FULL_GZ";
+          break;
+          case DeltaArchiveManifest_File_DataFormat_BSDIFF:
+          format = "BSDIFF";
+          break;
+          case DeltaArchiveManifest_File_DataFormat_COURGETTE:
+          format = "COURGETTE";
+          break;
+          default:
+            format = "???";
+        }
+        if (file.has_data_offset())
+          offset = file.data_offset();
+        if (file.has_data_length())
+          length = file.data_length();
+      }
+      printf("%s %o %s %d %d\n", it.path().c_str(), file.mode(), format, offset,
+             length);
+    }
+    exit(0);
+  }
+
+  CHECK(!FLAGS_delta.empty());
+  CHECK(!FLAGS_root.empty());
+  CHECK(!FLAGS_output_dev.empty());
+
+  // Create the single GMainLoop
+  GMainLoop* loop = g_main_loop_new(g_main_context_default(), FALSE);
+
+  chromeos_update_engine::TestInstaller test_installer(loop,
+                                                       FLAGS_root,
+                                                       FLAGS_delta,
+                                                       FLAGS_output_dev);
+
+  g_timeout_add(0, &chromeos_update_engine::TestInstallInMainLoop,
+                &test_installer);
+
+  g_main_loop_run(loop);
+  g_main_loop_unref(loop);
+
+  LOG(INFO) << "Done.";
+  return true;
+}
+
+}  // namespace chromeos_update_engine
+
+int main(int argc, char** argv) {
+  return chromeos_update_engine::Main(argc, argv) ? 0 : 1;
+}