Use pathlib2 (#636)

The dependency on `pathlib` was added in #631. A backport is needed for Python <3.4.

The `pathlib` package [on PyPI](https://pypi.org/project/pathlib/) is maintenance-only and comes with a message about using `pathlib2` for an up-to-date version, still importable as `pathlib`. Also `pytest` itself uses `pathlib2` so currently I'm getting both packages installed, one on top of the other, woops!

This change in `setup.py` seems to be all that's needed to switch.

pytest_django/plugin.py

@@ -11,7 +11,6 @@
 import sys
 import types
 
-import pathlib
 import pytest
 
 from .django_compat import is_django_unittest  # noqa
@@ -38,6 +37,11 @@
 
 from .lazy_django import django_settings_is_configured, skip_if_no_django
 
+try:
+    import pathlib
+except ImportError:
+    import pathlib2 as pathlib
+
 
 SETTINGS_MODULE_ENV = 'DJANGO_SETTINGS_MODULE'
 CONFIGURATION_ENV = 'DJANGO_CONFIGURATION'

setup.py

@@ -32,7 +32,7 @@ def read(fname):
     setup_requires=['setuptools_scm>=1.11.1'],
     install_requires=[
         'pytest>=3.6',
-        'pathlib;python_version<"3.4"',
+        'pathlib2;python_version<"3.4"',
     ],
     extras_require={
         'docs': [

tests/conftest.py

@@ -2,13 +2,17 @@
 import shutil
 from textwrap import dedent
 
-import pathlib
 import pytest
 import six
 from django.conf import settings
 
 from pytest_django_test.db_helpers import DB_NAME, TEST_DB_NAME
 
+try:
+    import pathlib
+except ImportError:
+    import pathlib2 as pathlib
+
 pytest_plugins = 'pytester'
 
 REPOSITORY_ROOT = pathlib.Path(__file__).parent