Utilising the mongoc driver, ive discovered that when you create a connection, using
client = mongoc_client_new(connection_string);

The returned value when the mongodb isnt running is not a null value. This means any tests/checks carried out do not catch that the server hasnt been connected to, causing issues further down the line.

Looking in the source I can't see anything that would set a value Null, either in v1.0.2, not v1.1.0 that was recently released.