Should human virtues be tested?

Once in world literature class, our respective professor quoted a saying from the poet Robert Browning “No virtue is virtue unless it has been tested”. I respect professor very much, since he is such a gentle and knowledgeable man, and of course, the great poet Robert Browning as well. Somehow, I don’t really agree with this point of view; by the way, professor ever said that he likes all of us to challenge his view. I think I’m going to try a bit.
Before we test our virtues, there are several questions to be considered, such as to what extent that we test the virtue? What is our purpose? I had read a story about a great captain who has adventured and experienced all around the world. He is well-known for his nobility and honesty. However, he betrays his best friend who is also his boss, because of the temptation of huge amount of money. Therefore, he lost his reputation, he ruins his career, and he destroys his life eventually, for he will bear the name of “betrayal” for the rest of his life. Yes, he was unable to prove his virtue and the test, but are we not being too cruel for setting up this kind of test? What will happen if he never encounters this test? Why do we purposely send a Lucifer to meet a person who has never experience wicked and evil?
In daily life, every minute, every second, every breath that we take, every step that we make, we are constantly tested by God. Let us focus and concentrate on our own test, pray harder that we can pass the test, so why bother to test other people? For nature of human is too weak to be tested, so please don’t try to test the least virtue that we have. Especially, don’t try to test your beloved’s loyalty.