refactor a mock server in client_test
refactor a mock server in client_test

wfxiang08/livegrep,paulproteus/livegrep,paulproteus/livegrep,lekkas/livegrep,wfxiang08/livegrep,paulproteus/livegrep,wfxiang08/livegrep,wfxiang08/livegrep,lekkas/livegrep,lekkas/livegrep,lekkas/livegrep,lekkas/livegrep,wfxiang08/livegrep,lekkas/livegrep,paulproteus/livegrep,paulproteus/livegrep,wfxiang08/livegrep,paulproteus/livegrep