The aliens did not give us the test until the governments of Earth unanimously requested it. They said if we passed the universe would be open to us.
The test was given to all of humanity. Nine billion people watched the aliens on television. A diagram was drawn, and billions of people copied it. The aliens then demonstrated how common materials could be used to build the simple machine shown on the diagram. Finally they explained that the machine would produce almost infinite energy. We could use it power starships or bombs.
It was a test of our collective character.