How to test the code issue after changing it ??
Welcome to the Tensorflow Forum!
If you are changing .py file you can clone repository and update those edited files in the place of original files and test using python /path-of-filename.py
Whereas in the case of C++ file, we need to build from source and then test the updated file using Bazel.
You can also refer to the open source contribution workflow here.
Thank you!