This is a sub-task offocused on the Update module.
In D8 per http://drupal.org/simpletest-tutorial-drupal7#t, best practice is to remove t() from assert messages in tests. When necessary, t() should be replaced with format_string().
There are approximately 23 changes needed in 4 Test files. This issue includes conversion of all format_patch() occurances as well (none were needed).