nunit-console is part of the NUnit unit-testing framework, it allows you to run your unit tests from the command line as seen here.
This image features an entrypoint for nunit-console. Attach a volume containing assemblies and set it as the working directory.
docker run -v "/path/to/assemblies:/test" --workdir /test itsverywindy/nunit-console [nunit console arguments]
Please report issues on the GitHub project.