Reorganize Python tests
diff --git a/src/python/grpcio_test/setup.py b/src/python/grpcio_test/setup.py
index dbea0f7..3f57ef0 100644
--- a/src/python/grpcio_test/setup.py
+++ b/src/python/grpcio_test/setup.py
@@ -31,7 +31,7 @@
 
 import setuptools
 
-_PACKAGES = setuptools.find_packages('.')
+_PACKAGES = setuptools.find_packages('.', exclude=['*._cython', '*._cython.*'])
 
 _PACKAGE_DIRECTORIES = {
     '': '.',