Hello Team,
I use:
Jenkins ver. 1.642.1,
Violations plugin ver. 0.7.11,
command to generate pep8 report:

py.test --pep8 /path/to/my/project/repo/ --junitxml=pep8.out | tee pep8.out;

The problem is violations plugin in per-file report shows "No violations found" when I click on the file link - link href:

http://jenkins_server/jenkins/job/JOB-NAME/violations/file//path/to/my/project/repo/file_name.py

When I follow the link - I see (without leading "/"):

path/to/my/project/repo/file_name.py
No violations found