CassandraDockerResource is a JUnit resource which can be used to write integration tests against a Cassandra server
executed inside an isolated Docker container.
DockerResource is a JUnit resource which starts up an isolated Docker container in a unit test, for example for
integration tests against an external database.
DockerResource will map the application ports, which are the ports applications listen to inside the container,
to random ports on the host machine, which can be used to communicate with the applications.
Subclasses can override this method in order to prepare a container once before tests are executed, for example by
initializing a database with a schema or inserting some application data into a database.