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unit-testingtestingtdd

Disadvantages of Test Driven Development?

What do I lose by adopting test driven design?

List only negatives; do not list benefits written in a negative form.

Solution

  • Several downsides (and I'm not claiming there are no benefits - especially when writing the foundation of a project - it'd save a lot of time at the end):

    • Big time investment. For the simple case you lose about 20% of the actual implementation, but for complicated cases you lose much more.
    • Additional Complexity. For complex cases your test cases are harder to calculate, I'd suggest in cases like that to try and use automatic reference code that will run in parallel in the debug version / test run, instead of the unit test of simplest cases.
    • Design Impacts. Sometimes the design is not clear at the start and evolves as you go along - this will force you to redo your test which will generate a big time lose. I would suggest postponing unit tests in this case until you have some grasp of the design in mind.
    • Continuous Tweaking. For data structures and black box algorithms unit tests would be perfect, but for algorithms that tend to be changed, tweaked or fine tuned, this can cause a big time investment that one might claim is not justified. So use it when you think it actually fits the system and don't force the design to fit to TDD.