Once a cub is deemed ready by their teachers--typically Tribesmates, but not always--the Rite Of Passage is performed. This ritual begins the test which will determine if the Tribal Totem considers the cub worthy of being considered a Cliath in the eyes of the Tribe and the Nation.
Somewhat confusingly, the actual event is also known as the cub's rite of passage. This can lead to some misunderstandings when you're discussing the ritual, instead of the test itself.
The test will vary by Tribe, auspice, and specific cub, but it is a defining event in the life of any Garou. Rites of passage can be done individually or in groups, and may be done in a variety of ways.
Upon the successful completion of their rite of passage, a cub is considered an adult in Garou society, and will often gain a new name (known as their Rite Name). They can also begin learning Cliath-level Gifts, and Rituals. On GarouMUSH, characters who are created as cubs and successfully pass their rite of passage gain 2 attribute points.
Not all cubs will succeed their rite of passage the first time, and death is not unheard of; it's not necessarily common, though, or there would be hardly any Garou left. A cub's teachers do not perform the ritual until they feel confident a cub has learned all they can, but in some cases a cub who is deemed incapable of becoming a Cliath will be put on their rite of passage in order for them to be returned to Gaia for rebirth and a new chance at becoming a Garou.