changed unit tests for image handle to reflect changes in observer, which now...

changed unit tests for image handle to reflect changes in observer, which now retains an internal reference to the observed image

modules/img/base/tests/test_image.cc

@@ -209,9 +209,10 @@ void test_Observer()
   }
   // ih and ih2 go out-of-scope
 
-  BOOST_CHECK(to1->release_count==1);
+  // observer retains internal reference, therefore no call to release should happen
+  BOOST_CHECK(to1->release_count==0);
 
-  BOOST_CHECK_THROW(to1->CheckData(), InvalidObserver);
+  BOOST_CHECK_NO_THROW(to1->CheckData());
 
   delete to1;
 }