Automated unit testing for COBOL development using Microfocus NetExpress. Any recommendations?

As often happens with Cobol systems, we have developers with only a few years of experience working on a codebase almost as old as they are. They are developing with Microfocus NetExpress and there's little desire to switch IDEs, although Eclipse might be an option. I'm keen to introduce automated unit testing to grow and expand the legacy code coverage, reduce risks after changes and shorten the feedback loop after commits. I know the options are limited, and some are simpler to adopt than others. Is anyone using Microfocus NetExpress to develop Cobol doing any automated unit testing? If so, what tools are you using? Ideally, I'm after recommendations from your own personal experience.