Elephant in Cairo

An elephant in Cairo is a term used in computer programming to describe a piece of test data that is designed to ensure that an algorithm is working. The term derives from a humorous essay circulated on the internet and published in Byte magazine that described how various professions would go about hunting elephants, with programmers following the algorithm:

:# Go to Africa. :# Start at the Cape of Good Hope. :# Work northward in an orderly manner, traversing the continent alternately east and west. :# During each traverse pass, :#:* Catch each animal seen. :#:* Compare each animal caught to a known elephant. :#:* Stop when a match is detected.

:EXPERIENCED COMPUTER PROGRAMMERS modify Algorithm A by placing a known elephant in Cairo to ensure that the algorithm will terminate.

The elephant would not, in practice, be part of the algorithm, but rather would be put into the test data that the algorithm is run against to ensure that it is working.