Specify test dependencies under extra_requires

Newer versions of pip/setuptools don't support test_requires, and the
current standard is to specify any extra dependencies (such as those
required for testing) under extra_requires.

Therefore, specify the testing dependencies under extra_requires. These
can be installed via pip using `pip install '.[testing]'`.

Signed-off-by: Saikrishna Arcot <[email protected]>

Author: saiarcot895

setup.py

@@ -269,6 +269,15 @@
         'mockredispy>=2.9.3',
         'deepdiff==6.2.2'
     ],
+    extras_require = {
+        'testing': [
+            'pyfakefs',
+            'responses',
+            'pytest',
+            'mockredispy>=2.9.3',
+            'deepdiff==6.2.2'
+        ],
+    },
     classifiers=[
         'Development Status :: 3 - Alpha',
         'Environment :: Console',