block(s)ByFragment: add test for simple case
block(s)ByFragment: add test for simple case

Cover https://coveralls.io/builds/4247897/source?filename=src%2Fnpge%2Fcpp%2Fmodel.cpp#L1093
Cover https://coveralls.io/builds/4247897/source?filename=src%2Fnpge%2Fcpp%2Fmodel.cpp#L1120

starius/lua-npge,npge/lua-npge,starius/lua-npge,npge/lua-npge,npge/lua-npge,starius/lua-npge