I seek refuge from You from such trials which may cause me...

I seek refuge from You from such trials which may cause me to go astray (means those trials, in which I may not come out successful and through it I may not be able to make myself perfect (accomplished) After that Imam Ali (a.s.) explains: The objective of the test and trials is not to gain information and insight, because in the universe there is not a thing which is hidden from or unseen by Allah.

The intention is that those hidden qualities say, like happiness and pleasure and anger or the portion of rage and fury which is given by Allah to become manifest and these hidden qualities come out in the form of action and apparent deeds, so that reward and punishment and merit of penalty and requital becomes manifest.

As you have observed, Imam (a.s.) has pointed out the purpose of test that, by them qualities and capabilities of man take the shape of apparent action and after this the person becomes competent for reward and punishment otherwise only on the basis of inner qualities (without the external acts) no reward or punishment can be given. And as a matter of fact in this situation perfection will not be achieved. For example when Allah commanded Hazrat Ibrahim (a.s.) to sacrifice Hazrat Ismail (a.s.).

When Allah tested him, His purpose is not to know whether Hazrat Ibrahim (a.s.) would obey His command or not, but, the intention is that, the soul which was present in the self of Hazrat Ibrahim (a.s.) which was eager to obey and accept the commands of Allah, the test will make it perfect, it will make it realize and take it into the stage of action and in this way Ibrahim (a.s.) will move on the road of perfection (Pay attention).

Hence, Allah puts everyone to test and trials by difficulties, hardship, distress and misfortunes; as He says: We will most certainly try you with somewhat of fear and hunger and loss of property and lives and fruits; and give good news to the patient. [Surah Baqarah 2:155] Difficulties and hardships are just like a furnace, which makes the iron hard and strong. Man also becomes strong and powerful in difficulties and misfortunes.

And he becomes capable of removing obstacles, which come in his way to a successful and happy life. When we say that, by taking tests, the purpose of Allah is to develop the latent good qualities in His servants it does not mean that all the persons who have undergone tests would necessarily develop good and likable qualities.