Test on PyPy Python 3 implementation

weakref test was adapted to explicitely call gc.collect(), other
tests pass without any modifications.

Also add supported Python implementations to classifiers.

1 files changed, 2 insertions, 0 deletions

diff --git a/setup.py b/setup.py
index 57fa425..3427cb3 100644
--- a/setup.py
+++ b/setup.py
@@ -33,6 +33,8 @@ setup(
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: Implementation :: CPython',
+        'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Software Development :: Libraries :: Python Modules'
     ]
 )