In general there are a lot of factors, in the example you give I would point out that it relates to cargo cult followers of a poor summarizations of best practices.
TDD/BDD proposes a world where all things work and remain working when investigated by an automated test. The automated test is built up step by step and happy to do everything from start to finish to look at the one feature and the feature may remain and continue to get repairs long after it continues to make any sense in a flow and with very little observation of how broken it might be in natural use.
TDD/BDD proposes a world where all things work and remain working when investigated by an automated test. The automated test is built up step by step and happy to do everything from start to finish to look at the one feature and the feature may remain and continue to get repairs long after it continues to make any sense in a flow and with very little observation of how broken it might be in natural use.