Alright, so here is the truth. I have been testing everyone's code, except my own! To be more precise, I've been involved in customer acceptance testing more than integration testing and NEVER in unit testing.
I started working early, so I practically never had much free time and never contributed to any open source projects. When I moved to Germany, I was pretty sure I could finally make time to contribute, thinking I was the one "giving".
The task I'm at is pretty easy, "write down the shunting yard algorithm and test it". Did the first part in a few minutes, and have been stuck for two to three days since! I mean... Testing was my job, it was what I did for 6 years, wasn't it!? I should've been way better at it!
I've been reading on and clicking on every single documentation page of GoogleTest to figure out where it goes wrong.
Apart from the frustration I feel, there's something else I feel as well, satisfaction. I am finally learning to "learn" and understanding that contribution isn't about me "giving" but also about me becoming aware of what I do not know.

P.S. probably very bad timing to get stuck on googleTest since I also have a couple of exams in October :-D