There will always be instances when you’d stop and think whether or not you've done everything on the list. Some jobs may never ever be concluded, such as doing the dishes in a 24-hour diner, but there will be breaks. You may be finished with washing the dishes today, but you'll do it again tomorrow, and someone else would be doing it in your place while you’re off-shift. Even if the diner transitioned to a banana leaf-plate, it’d only change the task, not the perpetuity of the task.
The same analogy can be applied for automated software testing. Software development may be a fluid cycle, but testing allows you to stop and ‘smell the roses’—primarily to look back and check or re-check your creation. To say that you're done means you've met all the requirements mandated by the project, and to do this, you need a record of sorts, a reference.
This the role of automated requirements traceability (ART). At this point, the development is at its final stages. All that ART demands is that you go over the list of requisites and check if you've done everything. ART documents everything from the get-go to record the results of prior tests, among others. If everything checks out, the software is ready for consumption.
The road to creating compliant software is lengthy and winding, but with software testing, you can take a break and enlist the help of people who deal with tech jargon every day.