Include all of our files in the distributions, and install packages
diff --git a/setup.py b/setup.py
index 7fe90d9..e1cc239 100644
--- a/setup.py
+++ b/setup.py
@@ -10,7 +10,7 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from setuptools import setup
+from setuptools import setup, find_packages
 
 about = {}
 with open("cryptography/__about__.py") as fp:
@@ -62,6 +62,8 @@
         "Topic :: Security :: Cryptography",
     ],
 
+    packages=find_packages(exclude=["tests", "tests.*"]),
+
     install_requires=install_requires,
     setup_requires=setup_requires,