proof
be (the) living proof that: seeliving.
the proof of the pudding is in the eating the real value of something can be judged only from practical experience or results and not from appearance or theory.
☞ Proof here means 'test', rather than 'verification'. A garbled version of the expression, the proof is in the pudding, is often heard, no doubt abbreviated for the sake of convenience.
2011Daily Telegraph Much of what Mr Cameron said is music to my ears. But the proof of the pudding is in the eating. Many obstacles will confront him if he tries to give effect in legislation to things he has said in his speech.