number of cores for travis

setup.py

@@ -8,6 +8,7 @@ from codecs import open
 
 from setuptools import setup
 from setuptools.command.test import test as TestCommand
+from multiprocessing import cpu_count
 
 here = os.path.abspath(os.path.dirname(__file__))
 
@@ -16,7 +17,7 @@ class PyTest(TestCommand):
 
     def initialize_options(self):
         TestCommand.initialize_options(self)
-        self.pytest_args = ['-n', '8', '--boxed']
+        self.pytest_args = ['-n', str(cpu_count()), '--boxed']
 
     def finalize_options(self):
         TestCommand.finalize_options(self)