how about this for the hypothesis dep

Author: altendky

setup.py

@@ -16,7 +16,7 @@
     python_requires='>=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*',
     install_requires=["greenlet", "pytest>=2.3", "decorator"],
     extras_require={
-        "dev": ["pre-commit", "black", "hypothesis"],
+        "dev": ["pre-commit", "black"],
         "pyside2": [
             # >= 0.6.3 for PySide2 extra version constraints
             "qt5reactor[pyside2]>=0.6.3",

tox.ini

@@ -11,6 +11,7 @@ deps=
     greenlet
     pytest
     twisted
+    hypothesis
     pyqt5reactor,pyside2reactor: pytest-qt
     pyqt5reactor,pyside2reactor: pytest-xvfb
     pyqt5reactor,pyside2reactor: pywin32; sys_platform == 'win32'