Add python_requires header

Author: nicoddemus

setup.py

@@ -169,6 +169,7 @@ def read(*parts):
         'Topic :: Software Development :: Libraries :: Python Modules',
         'Topic :: Software Development :: Testing',
     ],
+    python_requires=">=3.5",
 
     # The following makes the plugin available to pytest
     entry_points={

tests/test_live_server.py

@@ -42,7 +42,7 @@ def test_a(live_server):
                     'example.com:%d' % live_server.port
         ''')
 
-        result = appdir.runpytest('-v', '-o=live_server_scope=function')
+        result = appdir.runpytest('-v', '-o', 'live_server_scope=function')
         result.stdout.fnmatch_lines(['*PASSED*'])
         assert result.ret == 0