TDD Works Best for Predictable Tasks; Use Spikes for Exploratory Work

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Test-Driven Development (TDD) is most effective when requirements, inputs, and expected outputs are clearly defined before coding begins, such as in standard APIs or utility functions. When tackling ambiguous problems — like integrating a poorly documented third-party API — writing tests upfront leads to repeated rewrites as the solution shape remains unknown. In such exploratory phases, developers are better served by a 'spike': throwaway, unstructured code written purely to discover how a system behaves. Once a spike reveals a working solution, the prototype should be discarded and clean production code written using TDD. The core principle is matching the development approach to the level of predictability in the task at hand.

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ProgrammingDEV Community ·

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