The proof of the pudding is in the eating...

My verdict: yum, yum!

'The proof of the pudding is in the eating' is an ancient proverb.

The Oxford Dictionary of Quotations dates it back to the early 14th century. Although some would attribute the phrase to Cervantes (The History of Don Quixote), some scholars believe that this was not even known to Cervantes, and the earliest printed example of this adage is in William Camden's Remaines of a Greater Worke Concerning Britaine, 1605:

"All the proof of a pudding is in the eating."

In 1682, a  translation by Nicolas Boileau-Despréaux Le Lutrin (written between 1672 and 1674) reads: "The proof of th' pudding's seen i' the eating."

When used, this idiomatic expression means: to fully know or understand something (test), you have to experience it.