Andrei Neagoie's Complete Junior to Senior course does a great job of covering a lot of topics. Including automating tests with CI/CD through CircleCI. However, a lot of people have been moving away from tools like CircleCI in favor of GitHub actions.
You might not be using GitHub at work and instead using GitLab or BitBucket, but GitHub actions are the best way to handle CI today. Most tasks can be done by grabbing an action off the marketplace and plugging it in to a YML file.
Brian Douglas' course takes one small step forward by going over how to code your own GitHub apps and actions. Which can help you develop custom solutions for the repositories you manage.
The course itself feels pretty basic. You won't be building a big pipeline. Rather, this is just a short overview of what you can do and how to do it. That's generally ok for the subject but I would have liked to see something more robust.
Brian's delivery sometimes comes off as unprepared as he has to double back on his own words a lot and I would have liked a summary of what he was going to cover from the start. As I watched through the videos I had no idea where things were going or if this whole endeavor would even be worth my time.
But if you're not already familiar with GitHub actions I definitely recommend this course. That's why I'm giving Brian Douglas' Code Automation With GitHub a 4 out of 5.