I am debugging decode_raw_op_test from TensorFlow. The test file is written in python however it executes code from underlying C++ files. 
Using pdb, I could debug python test file however it doesn't recognize c++ file. Is there a way in which we can debug underlying c++ code?
(I tried using gdb on decode_raw_op_test but it gives "File not in executable format: File format not recognized")
Adding on mrry's answer, in today's TF2 environment, the main entry point would be TFE_Execute, this should be where you add the breakpoint.
Debugging TensorFlow tests: pdb or gdb?