The Quran is in fact clear, God doesn't know who will strive among us, and who will not, beforehand, he is testing us in real time.
No .. if G-d is not omniscient, then how could any prophet be informed [ by G-d ] of any future events, such as the signs of the last days?
Time belongs to G-d, the creator of the universe.
Einstein shows us that the universe is a space-time continuum.
It is not just a religious belief, it is demonstrated in science, that time is a dimension of the universe.
It follows that G-d is not part of His creation, and therefore sees all.
This does not take away our free-will, or examination of our behaviour. Mankind is being tested in real-time, as you say.
It is our reality, but G-d's perception is different.
He is the Master of the universe. He is the true time-lord !