In this blog post Mohammad Azam will discuss that the table names are important in MongoDb document database.
After fighting this bug for hours I finally figured it out. For some reason my unit test below was constantly failing with Object Ref error.
This was also causing other problems with Repositories testing. On the other hand the following test passes:
The "." in the table name was causing the problem. Make sure to NOT use "." in table names when using MongoDb.