Remove pytest-runner dependency

To support "python setup.py test", add a setuptools command
within setup.py to achieve this.  the pytest-runner needlessly
requires a global build requirement.

Author: zzzeek

setup.cfg

@@ -5,5 +5,3 @@ addopts= --tb native -v -r fxX --ignore=sqlalchemy
 python_files=sqlalchemy_collectd/*/test_*.py
 
 
-[aliases]
-test=pytest

setup.py

@@ -1,7 +1,9 @@
 from setuptools import setup
 from setuptools import find_packages
+from setuptools.command.test import test as TestCommand  # noqa
 import os
 import re
+import sys
 
 
 with open(
@@ -18,6 +20,26 @@
     'SQLAlchemy>=1.1',
 ]
 
+
+class PyTest(TestCommand):
+    user_options = [('pytest-args=', 'a', "Arguments to pass to py.test")]
+
+    def initialize_options(self):
+        TestCommand.initialize_options(self)
+        self.pytest_args = []
+
+    def finalize_options(self):
+        TestCommand.finalize_options(self)
+        self.test_args = []
+        self.test_suite = True
+
+    def run_tests(self):
+        # import here, cause outside the eggs aren't loaded
+        import pytest
+        errno = pytest.main(self.pytest_args)
+        sys.exit(errno)
+
+
 setup(
     name='sqlalchemy-collectd',
     version=VERSION,
@@ -38,7 +60,7 @@
     packages=find_packages(".", exclude=["*.tests"]),
     include_package_data=True,
     tests_require=['pytest', 'mock'],
-    setup_requires=['pytest-runner'],
+    cmdclass={'test': PyTest},
     zip_safe=False,
     install_requires=requires,
     entry_points={