Update the contributor guide

Add missing tox targets in contributor/testing.rst.
Replace the launchpad link to nova project with
the launchpad link to python-novaclient project
in contributor/index.rst.

Change-Id: I1b3736f25e59669624331d8f86820a45181c6760
Closes-Bug: #1795353

doc/source/contributor/index.rst

@@ -2,12 +2,12 @@
  Contributor Guide
 ===================
 
-Code is hosted at `git.openstack.org`__. Submit bugs to the Nova project on
-`Launchpad`__. Submit code to the `openstack/python-novaclient` project using
-`Gerrit`__.
+Code is hosted at `git.openstack.org`__. Submit bugs to the python-novaclient
+project on `Launchpad`__. Submit code to the `openstack/python-novaclient`
+project using `Gerrit`__.
 
 __ https://git.openstack.org/cgit/openstack/python-novaclient
-__ https://launchpad.net/nova
+__ https://bugs.launchpad.net/python-novaclient
 __ https://docs.openstack.org/infra/manual/developers.html#development-workflow
 
 .. toctree::

doc/source/contributor/testing.rst

@@ -6,16 +6,22 @@ The preferred way to run the unit tests is using ``tox``. There are multiple
 test targets that can be run to validate the code.
 
 ``tox -e pep8``
-
   Style guidelines enforcement.
 
 ``tox -e py27``
+  Traditional unit testing (Python 2.7).
 
-  Traditional unit testing.
+``tox -e py35``
+  Traditional unit testing (Python 3.5).
 
 ``tox -e functional``
+  Live functional testing against an existing OpenStack instance. (Python 2.7)
 
-  Live functional testing against an existing OpenStack instance.
+``tox -e functional-py35``
+  Live functional testing against an existing OpenStack instance. (Python 3.5)
+
+``tox -e cover``
+  Generate a coverage report on unit testing.
 
 Functional testing assumes the existence of a `clouds.yaml` file as supported
 by `os-client-config <https://docs.openstack.org/os-client-config/latest>`__