My situation is as follows, I am an entry level programmer having been assigned my first real project.
I'm supposed to be part of a 3 man team which develops a new part of the application, the others being a fellow new employee I was partnered with during the training and a senior programmer who trained us.
The problem is that during the first stages of the project the senior was pulled into other projects and we juniors had to do things as we knew (it's a new technology for the firm, and that's why we juniors were "apprenticed" to this senior).
And we made mistakes in the code, in our workflow and we didn't progress at a good speed.
What is causing me stress and trouble at the workspace is that I feel I'm being singled out for errors both we juniors did.
My junior colleague works only part time due to still being a student, yet our supervisor only comes to check the code when he is away and I end up taking the blame for shared problems in the code and his own problems in the code.
There's only so many times I can say "This is X's area of code, but I'll try to fix it!" then fix it,eventually I just silently note down the problems whether they are in mine/his/shared and get to fixing it.
Yet I am the face the supervisor sees when the code is found faulty and I'm right now solidly established as the "slow and sloppy" worker.
To add insult to injury after fixing the errors in my and his code, I still put in the hours to add new features to the project. These features get tested first and problems are found. Meanwhile, my colleague's work sits there untested, accumulating fixes I already figured out, resulting in work which seems faster and more error free than mine.
How can I explain my point of view without looking like I want to throw my colleague under the bus ?
Edit:
Just wanted to add some clarifications, yes we are using source control for the code, but using the blame command to show the errors in my colleague's code raises the same problem it shows that as a programmer my code is not uniquely flawed yet it marks me as the coworker who is trying to share the blame.