Short positive feedback loops in software development are important.
Looking at what happened in the past, we can suggest what could be done to improve the situation in the future. It’s fundamental to lean and agile methodologies. Indeed, the methodologies themselves encourage adaptation of the methodologies by teams to adapt the practices and processes locally.
Test Driven Development (and it’s variants and corollaries) are all about this feedback, they help you think about what you’re doing immediately by showing you straight away. For instance, you can decide there and then that you don’t like the name of something (perhaps it turns out it doesn’t describe the intent). Feedback from you using your code can improve how you design your code.
People strive for fast running tests - they help keep developers upbeat. Slow builds sap the patience and take focus away from writing code and introduce unnecessary context switching. Slow tests become a pain, and people find ways to try and get around having to run them. Feedback is discarded.
To my mind, this is exactly why trying to split off the writing of tests to separate developers is costly - tests are a valuable learning tool, they provide a continuous response to you.
Write a nice clean test that results in simple and expressive code feels good, bad test phrasing feels dirty. Take yourself away from the feedback and you lose the opportunity to gain those insights. It may be that you spend most of your time working with developer tests, but having acceptance tests up-front that can direct your effort provide a great communication tool.
Keep yourself close to the feedback.