是騾子是馬，牽出來遛遛 [－骡－－马－牵－来－－]

Jyutping
Pinyin shì luó zi shì mǎ , qiān chū lai liù liu

Definitions (CC-CEDICT)
  1. lit. to see whether it's a mule or a horse, take it out for a walk (idiom)
  2. fig. the proof of the pudding is in the eating
  3. to show what one is made of