是骡子是马，牵出来遛遛 (是騾子是馬，牽出來遛遛) shì luózi shì mǎ, qiān chūlái liù liù

shì luózi shì mǎ, qiān chūlái liù liù phrase to see whether it's a mule or a horse, take it out for a walk; the proof of the pudding is in the eating
Domain: Proverb 谚语
Notes: (CC-CEDICT '是騾子是馬，牽出來遛遛')