For some country+region combos, region_name might not be found, which results in a NULL string and causes segfault when strlen() is performed on it. Move `region_name` variable definition to conform C89 and please some compilers. Add a test that verifies the fixed behavior.
Without it, Ruby 1.9.x can't read the test file. Rake::TestTask automatically adds 'lib' directory to $LOAD_PATH.