/testfor: 检查是否存在符合选择器的实体，并统计数量。
语法
<尖括号> 内为必填，[方括号] 内为可选。
/testfor <victim: selection>/testfor
命令: 命令
全部命令 ·/aimassist ·/allowlist ·/camera ·/camerashake ·/changesetting ·/clear ·/clearspawnpoint ·/clone ·/controlscheme ·/damage ·/daylock ·/deop ·/dialogue ·/difficulty ·/editor-allowlist ·/effect ·/enchant ·/event ·/execute ·/fill ·/fog ·/function ·/gamemode ·/gamerule ·/gametest ·/give ·/help ·/hud ·/inputpermission ·/kick ·/kill ·/list ·/locate ·/loot ·/me ·/mobevent ·/music ·/op ·/packstack ·/particle ·/permission ·/place ·/playanimation ·/playsound ·/project ·/recipe ·/reload ·/reloadconfig ·/reloadpacketlimitconfig ·/replaceitem ·/ride ·/save ·/say ·/schedule ·/scoreboard ·/script ·/scriptevent ·/sendshowstoreoffer ·/serveridentity ·/setblock ·/setmaxplayers ·/setworldspawn ·/spawnpoint ·/spreadplayers ·/stop ·/stopsound ·/structure ·/summon ·/tag ·/teleport ·/tell ·/tellraw ·/testfor ·/testforblock ·/testforblocks ·/tickingarea ·/time ·/title ·/titleraw ·/toggledownfall ·/transfer ·/weather ·/wsserver ·/xp