This is something quite interesting that I ran across today - NoSQLUnit 0.3.2. I didn't realize that there was a project out there like this, very cool!
Some NoSQL projects are easier to run embedded than others, and this could certainly help that. You always need help classes to facilitate running unit tests against a data source. I've writing unit tests against ElasticSearch, which has a local/memory mode that is great for writing tests against. Still, you have to generate your test data and load it into the search engine for testing.