Could the Universe Be a Test?

Yes—depending on the lens you use.

In religion, many traditions treat life as a test of faith, character, free will, or karma.
In philosophy, especially Stoicism, the point is less that the universe was designed as a test and more that we can choose to face hardship as one.
In science, the idea isn’t currently testable. A “universe as a test” can’t be proven or disproven unless it leaves clear, measurable evidence.

So the best short answer is: it can be a meaningful belief or framework, but not a scientific conclusion.