Testing is the practise of electronically identifying the abilities, Dwelling, Animal and colour of a person who has Fire Eyes. 'Abilities' testing was created in 2004, and is practised in most Headquarters around the world. The original form of testing, without the 'Abilities' prefix, did not find abilities, as it did not require the use of technology and could only find a person's Dwelling and Animal.
Testing was not technical at all until the 2004 remake. Before then, once the Dwelling was discovered, it would only be a matter of encountering one's designated Animal. Of course, this was very difficult to do. Arenas were set up, filled with animals that a Dwelling belonged to. Whichever animal that person could communicate with would be their designated Animal. This style of testing was controversial upon the Founders' deaths, as some Dwellings carried several types of animal that could may well kill each other For example, the Surface Dwelling consists of common fish and mammals, so a real-life shark could, per say, 'eat a Goldfish'. It was later proved, however, that a person of a particular Dwelling could get along suitably with other animals that were carried in their Dwelling (meaning that a Goldfish would still be able to exist alongside a shark in the water).
If a person could not easily find their Dwelling, which occured occasionally due to some people having traits of one or more Dwellings, e.g. a very flexible, white-eyed person with a natural scent like that of the colour pink, a chart could be used. It would be likely that a person could narrow their possible Dwellings to less than four, but even in extremely mixed cases, a person could go into every individual arena and search for their Animal. Or, if they already know their Animal, they could just encounter it once in front of a tester. Once the Animal is found, a Dwelling Chart can be used. It classifies all living creatures into categories, as all Animals fit into one Dwelling. This method of finding one's Dwelling was also controversial, especially with the introduction of Animal Justification.
The Water Dwelling, using the original testing method, could not identify its animals. The animals were either too hard to find, or polar. Until the remake, the law allowed Water Dwellers to choose their own Animal, as long as it was realistic alongside their abilities.