I'm attaching a test for Ctrl-C behavior on Linux (the patch itself works on Windows too, but I am not sure how to send Ctrl-C on windows programatically and subprocess does not have this functionality either).
The test_pdb2.py module is generic and can be extended to test other functionality. But, as discussed earlier, it cannot be easily (if at all) integrated into existing test_pdb.py.
Note that the test module will NOT work with existing pdb (as it doesnot have expected Ctrl-C) behavior, but on can specify alternative pdb location from command line:
env DEBUG_PDB=./pdb.py ./test_pdb2.py