Connection leaks in adapter tests

[relekang]

The adapter tests does not close connection correctly resulting in tests for the redis adapter never quitting.

The problem is the at the moment is call init should not throw. Overwrites the connections with new one and then when the tests closes connection in afterEach the connection created in beforeEach is not closed.

I think it would be a good thing to require adapter.close() and handle the closing of database connections in the adapter utils.