Refactor automatic cpu detection code to auto_detect_cpus()

xdist/plugin.py

@@ -4,8 +4,7 @@ import py
 import pytest
 
 
-def parse_numprocesses(s):
-    if s == 'auto':
+def auto_detect_cpus():
     try:
         from os import sched_getaffinity
     except ImportError:
@@ -25,6 +24,11 @@ def parse_numprocesses(s):
     except NotImplementedError:
         return 1
     return n if n else 1
+
+
+def parse_numprocesses(s):
+    if s == 'auto':
+        return auto_detect_cpus()
     else:
         return int(s)