Install by running the command:

pip install pytest-flake8

After installing it, when you run tests with the option:

py.test --flake8

every file ending in .py will be discovered and checked with flake8.

Maximum line length can be configured for the whole project by adding a flake8-max-line-length option to your setup.cfg or tox.ini file like this:

# content of setup.cfg
[pytest]
flake8-max-line-length = 99

Note that the default will be what naturally comes with flake8 (which it turn gets its default from pep8).

You may configure flake8-checking options for your project by adding an flake8-ignore entry to your setup.cfg or tox.ini file like this:

# content of setup.cfg
[pytest]
flake8-ignore = E201 E231

This would globally prevent complaints about two whitespace issues. Rerunning with the above example will now look better:

$ py.test -q  --flake8
collecting ... collected 1 items
.
1 passed in 0.01 seconds

If you have some files where you want to specifically ignore some errors or warnings you can start a flake8-ignore line with a glob-pattern and a space-separated list of codes:

# content of setup.cfg
[pytest]
flake8-ignore = 
    *.py E201
    doc/conf.py ALL

So if you have a conf.py like this:

# content of doc/conf.py

func (  [1,2,3]) #this line lots pep8 errors :)

then running again with the previous example will show a single failure and it will ignore doc/conf.py alltogether:

$ py.test --flake8 -v # verbose shows what is ignored
======================================= test session starts ========================================
platform darwin -- Python 2.7.6 -- py-1.4.26 -- pytest-2.7.0 -- /Users/tholo/Source/pytest/bin/python
cachedir: /Users/tholo/Source/pytest/src/verify/.cache
rootdir: /Users/tholo/Source/angular/src/verify, inifile: setup.cfg
plugins: flake8, cache
collected 1 items

myfile.py PASSED

========================================= 1 passed in 0.00 seconds =========================================

Note that doc/conf.py was not considered or imported.

The repository of this plugin is at https://github.com/tholo/pytest-flake8

For more info on py.test see http://pytest.org

The code is partially based on Ronny Pfannschmidt's pytest-codecheckers plugin.