Bug 1254 - increase unit test coverage

- added trivial tests for NxmExtensionsConvertor.java

Change-Id: Ic3bd931f70dbd5269e7286a060c4430e9c5d4ee7
Signed-off-by: Martin Bobak <mbobak@cisco.com>
Bug 1254 - increase unit test coverage

Change-Id: Id7797341a91c166ada906b6ce3cadc7606311061
Signed-off-by: Martin Bobak <mbobak@cisco.com>