There is a way to pass fixtures from python code to tests via plugins argument of pytest.main().

Creating fixture

To create fixture we can use decorator @pytest.fixture:

@pytest.fixture
def info(request):
    return "Information!"

Passing plugin to pytest

To pass something to pytest-executed tests we can use plugin mechanism of pytest. (For not let says that myplugin contains actual plugin, I’ll show later how to create it).

pytest.main([path_to_test, '-v'], plugins=[myplugin])

Please not that plugins takes a list of plugins, not plugin itself

Creating plugin

There are two ways to create plugin:

• Use stand-alone module
• Create class or other dotted object (object with members accessible by dot: plugin.something).

Module way

Use a separate file to contains plugin code:

myplugin.py:

import pytest

@pytest.fixture
def info(request):
    return "Information"

actual call of pytest:

import myplugin

pytest.main(['mytest.py', '-v'], plugins=[myplugin])

Fixture usage (mytest.py):

def test_foo(info):
    assert info() == "Information"

Class way

This way I found more preferable, because I have higher degree of freedom during class initialization. I can put all information I want inside class in very natural way.

Plugin and fixture constuction and test call:

import pytest

class MyPlugin(object):
    def __init__(self, data):
        self.data = data

    @pytest.fixture
    def info(self, request):
        return self.data

myplugin = MyPlugin('information')

pytest.main("mytest.py", plugins=[myplugin])

Test is exactly the same as before (mytest.py):

def test_foo(info):
 assert info() == "Information"

More than one fixture

It is very easy to put any number of fixtures into a class:

import pytest

class MyPlugin(object):
    def __init__(self, data):
        self.data = data

@pytest.fixture
    def info(self, request):
        return self.data

@pytest.fixture
    def length(self, request):
        return len(self.data)

myplugin = MyPlugin('information')

pytest.main("mytest.py", plugins=[myplugin])

A bit upgraded version of the test accepts two fixtures (mytest.py):

def test_foo(info, length):
 assert len(info()) == length()