The Portal 2 Test Generator (P2TG for short) is an open-source project that aims outputs .p2c files, which will be able to be opened in the Portal 2 editor and will be fully functioning.
Of course, just fork this project and when your finish make a pull request to the dev branch.
Click on the Issues tab then click New Issue and then suggest/report away!
It very much depeneds on how much traffic this project gets, if it gets none, then it's likely to be within three years, but if it gets a good amount of help, it should be work within <8 months.