porting those unit tests feels strange as I need to copy paste a specific version of the qofono lib headers for the mock library @Kaffeine do you think we might be able to use ofono-phonesim for testing instead?

It would be much better to use ofono-phonesim, but I have no idea if it is actually doable.

It seems like I'm having some issues to get account manager to run? the ConnectionTest hangs in TelepathyHelper::instance() and If I make that test fail before that line I get the following warning in output:

tp-qt 0.9.7 WARN: Error parsing config file for connection manager "ofono" - introspecting 

It seems like I'm having some issues to get account manager to run? the ConnectionTest hangs in TelepathyHelper::instance() and If I make that test fail before that line I get the following warning in output:

tp-qt 0.9.7 WARN: Error parsing config file for connection manager "ofono" - introspecting 

Telepathy spec says that connection manager should provide a config file with list of its protocols and capabilities (however clients must have a fallback mechanism that get the needed info by activating the connection manager and calling its methods).
TelepathyQt tests overcome this warning by modifying XDG_DATA_HOME environment variable: https://github.com/TelepathyIM/telepathy-qt/blob/master/tests/CMakeLists.txt#L6

I have some time and I'm going to try this branch right now :).

Meh, telepathy-ofono already has CMake code for that.
If you run the tests via cmake --build . --target test or ctest -VV you'll see that it sets a lot of env vars.