Adding in most of the unit tests.

tests/common/win/testing_common.cc

 /*
  * Copyright 2009, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 142 matching lines @@
   g_renderer = o3d::Renderer::CreateDefaultRenderer(g_service_locator);
 
   // Initialize the renderer for off-screen rendering if kOffScreenRenderer
   // is in the environment.
   bool success;
   o3d::DisplayWindowWindows* display_window =
       new o3d::DisplayWindowWindows();
   display_window = display_window;
   display_window->set_hwnd(g_window_handle);
   g_display_window = display_window;
-  bool offscreen = ::GetEnvironmentVariableW(kOffScreenRenderer, NULL, 0);
+  bool offscreen = (::GetEnvironmentVariableW(kOffScreenRenderer,
+                                              NULL, 0) == 0);
   if (offscreen) {
     success =
         g_renderer->Init(*g_display_window, true) == o3d::Renderer::SUCCESS;
   } else {
     success =
         g_renderer->Init(*g_display_window, false) == o3d::Renderer::SUCCESS;
     if (success) {
       ::SetWindowPos(g_window_handle, HWND_TOPMOST, 0, 0, 0, 0,
                      SWP_NOMOVE | SWP_NOSIZE);
       ::ShowWindow(g_window_handle, SW_SHOWNORMAL);
@@ skipping 19 matching lines @@
   delete g_renderer;
   g_renderer = NULL;
 
   delete display_window;
   g_display_window = NULL;
   g_program_path = NULL;
   g_program_name = NULL;
 
   return ret;
 }