py.test plugin for efficiently checking PEP8 compliance

Usage

install via:

pip install pytest-pep8

if you then type:

py.test --pep8

every file ending in .py will be discovered and pep8-checked, starting from the command line arguments.

# content of setup.cfg (or pytest.ini)
[pytest]
pep8ignore = * ALL

A little example

If you have a pep8-violating file like this:

# content of myfile.py

somefunc( 123,456)

you can run it with the plugin installed:

$ py.test --pep8
=========================== test session starts ============================
platform linux2 -- Python 2.7.6 -- py-1.4.30 -- pytest-2.7.2
rootdir: /tmp/doc-exec-2, inifile: 
plugins: pep8, cache
collected 1 items

myfile.py F

================================= FAILURES =================================
________________________________ PEP8-check ________________________________
/tmp/doc-exec-2/myfile.py:2:10: E201 whitespace after '('
somefunc( 123,456)
         ^
/tmp/doc-exec-2/myfile.py:2:14: E231 missing whitespace after ','
somefunc( 123,456)
             ^

========================= 1 failed in 0.00 seconds =========================

For the meaning of (E)rror and (W)arning codes, see the error output when running against your files or checkout pep8.py.

Let's not now fix the PEP8 errors:

# content of myfile.py
somefunc(123, 456)

and run again:

$ py.test --pep8
=========================== test session starts ============================
platform linux2 -- Python 2.7.6 -- py-1.4.30 -- pytest-2.7.2
rootdir: /tmp/doc-exec-2, inifile: 
plugins: pep8, cache
collected 1 items

myfile.py .

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

the pep8 check now is passing. Moreover, if you run it once again (and report skip reasons):

$ py.test --pep8 -rs 
=========================== test session starts ============================
platform linux2 -- Python 2.7.6 -- py-1.4.30 -- pytest-2.7.2
rootdir: /tmp/doc-exec-2, inifile: 
plugins: pep8, cache
collected 1 items

myfile.py s
========================= short test summary info ==========================
SKIP [1] /home/hpk/p/pytest-pep8/pytest_pep8.py:65: file(s) previously passed PEP8 checks

======================== 1 skipped in 0.00 seconds =========================

you can see that the pep8 check was skipped because the file has not been modified since it was last checked. As the pep8 plugin uses the pytest-cache plugin to implement its caching, you can use its --clearcache option to remove all pytest caches, among them the pep8 related one, which will trigger the pep8 checking code to run once again:

$ py.test --pep8 --clearcache
=========================== test session starts ============================
platform linux2 -- Python 2.7.6 -- py-1.4.30 -- pytest-2.7.2
rootdir: /tmp/doc-exec-2, inifile: 
plugins: pep8, cache
collected 1 items

myfile.py .

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

Configuring PEP8 options per project and file

You may configure PEP8-checking options for your project by adding an pep8ignore entry to your setup.cfg or setup.cfg file like this:

# content of setup.cfg
[pytest]
pep8ignore = E201 E231

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

$ py.test -q  --pep8
.
1 passed in 0.00 seconds

If you have some files where you want to specifically ignore some errors or warnings you can start a pep8ignore line with a glob-pattern and a space-separated list of codes:

# content of setup.cfg
[pytest]
pep8ignore = 
    *.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 --pep8 -v # verbose shows what is ignored
=========================== test session starts ============================
platform linux2 -- Python 2.7.6 -- py-1.4.30 -- pytest-2.7.2 -- /home/hpk/venv/clean/bin/python
cachedir: /tmp/doc-exec-2/.cache
rootdir: /tmp/doc-exec-2, inifile: setup.cfg
plugins: pep8, cache
collecting ... collected 1 items

myfile.py PASSED

========================= 1 passed in 0.01 seconds =========================

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

If you'ld like to have longer lines than 79 chars (which is the default for the pep8 checker), you can configure it like this:

# content of setup.cfg
[pytest]
pep8maxlinelength = 99

Running PEP8 checks and no other tests

You can also restrict your test run to only perform "pep8" tests and not any other tests by typing:

py.test --pep8 -m pep8

This will only run test items with the "pep8" marker which this plugins adds dynamically.

Notes

The repository of this plugin is at

For more info on py.test see

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