Good article as usual, I'd argue that in TDD preconditions are absolutely critical because otherwise your tests cannot possibly be considered complete. At the e

Good article as usual, I'd argue that in TDD preconditions are absolutely critical because otherwise your tests cannot possibly be considered complete. At the end of the day preconditions usually amount to if (valid) continue else throw If they did turn out to be a bottleneck in the future then modifying or even removing them shouldn't affect visible behavior.