It is actually easy and obvious once experiencing a real agile project works. Many classic agile books have already talked about it, see the quotes in the article.
I think you, like many, know that shall be the case, but don't believe it is possible, in reality.
"Facebook release twice a day"
"LinkedIn push updates to production multiple times a day" https://zhiminzhan.medium.com/analyses-of-the-wired-article-the-software-revolution-behind-linkedins-gushing-profits-b9496d04d0a3
I have been doing "Daily production releases" for all my apps (quite complex ones) for 10+ years. A Show case: https://zhiminzhan.medium.com/showcase-a-500-end-to-end-via-ui-test-suite-e2e-test-automation-is-surely-feasible-for-590a45992a23
Regardless big or small companies, this is achievable. Please note, the CEO/CIO is directly behind this. In other words, they take automated E2E regression testing really seriously. for my company, certainly No.1, above anything activity. Based on my estimation, My company spent 70% of whole software development effort on E2E Test Automation + Continuous Testing, in return, we gained at least 50X (compared to equivalent competitors) productivity. My apps are solid proof.
With that context, I can answer your question directly.
1. Coverage
We don't use Jira or any digitial requirement tool (see the comment from Kent Beck, father of Agile). For every user story, we write at least one automated E2E test to verify. It is "Done, Done" in Agile.
https://zhiminzhan.medium.com/done-done-in-agile-8cd95f077411
If every user story is covered, of course, the whole is covered.
2. Execution
All automated UI Tests (as a whole suite) will be run frequently. Due to resource limit, I don't achieve "10 minute feedback to developer" after a code check-in, but not too far. Multiple full automated regression testing a day.
If the E2E tests (covering all user stories) are running every a few hours, anyone can manage it. I implemented this for a dozens of clients. It is very logical.
3. Dealing with defects
If there is a report defect, we just replicate it in automated E2E tests (new or updated), then included in the next execution, maybe in a few minutes time.
This way, we don't worry writing them down (mostly got incorrect or outdates quickly) in Jira or Quality Center. Our E2E test script is written in a format (RSpec) that a business analyst (even customer) can understand.
Once I implemented this process over a decade ago, Agile/DevOps made sense. Sadly, few companies and software projects would invest effort to learn and do hands-on automated E2E testing.
