Dagster University has announced a new course on testing with Dagster, emphasizing the importance of testing in data engineering to build with confidence. The six-lesson course covers various aspects of testing, including unit testing, asset tests, integration testing, and best practices for handling external dependencies. It also provides examples, such as mocking API calls, to demonstrate how to test Dagster code effectively. The course is free and available to everyone, allowing users to track their progress and learn at their own pace.