In TestDrivenDevelopment, EliminateDuplication is the goal of the ReFactoring step that comes between getting the UnitTest''''''s to pass and proceeding to the next UnitTest.

The goal of EliminateDuplication is to arrive at code that says everything OnceAndOnlyOnce.

See OnceAndOnlyOnce
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CategoryExtremeProgramming CategoryTestDrivenDevelopment