chore(python): simplify nox steps in CONTRIBUTING.rst (#130)

Source-Link: googleapis/synthtool@26558ba
Post-Processor: gcr.io/repo-automation-bots/owlbot-python:latest@sha256:99d90d097e4a4710cc8658ee0b5b963f4426d0e424819787c3ac1405c9a26719

chore: Update CONTRIBUTING.rst to reflect supported versions

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -1,3 +1,3 @@
 docker:
   image: gcr.io/repo-automation-bots/owlbot-python:latest
-  digest: sha256:df50e8d462f86d6bcb42f27ecad55bb12c404f1c65de9c6fe4c4d25120080bd6
+  digest: sha256:99d90d097e4a4710cc8658ee0b5b963f4426d0e424819787c3ac1405c9a26719

CONTRIBUTING.rst

@@ -68,14 +68,12 @@ Using ``nox``
 We use `nox <https://nox.readthedocs.io/en/latest/>`__ to instrument our tests.
 
 - To test your changes, run unit tests with ``nox``::
+    $ nox -s unit
 
-    $ nox -s unit-3.8
-    $ ...
+- To run a single unit test::
 
-- Args to pytest can be passed through the nox command separated by a `--`. For
-  example, to run a single test::
+    $ nox -s unit-3.9 -- -k <name of test>
 
-    $ nox -s unit-3.8 -- -k <name of test>
 
   .. note::
 
@@ -142,7 +140,7 @@ Running System Tests
 - To run system tests, you can execute::
 
    # Run all system tests
-   $ nox -s system-3.8
+   $ nox -s system
 
    # Run a single system test
    $ nox -s system-3.8 -- -k <name of test>
@@ -215,8 +213,8 @@ Supported versions can be found in our ``noxfile.py`` `config`_.
 .. _config: https://github.com/googleapis/google-auth-library-python-oauthlib/blob/master/noxfile.py
 
 
-We also explicitly decided to support Python 3 beginning with version
-3.6. Reasons for this include:
+We also explicitly decided to support Python 3 beginning with version 3.6.
+Reasons for this include:
 
 -  Encouraging use of newest versions of Python 3
 -  Taking the lead of `prominent`_ open-source `projects`_

noxfile.py

@@ -28,7 +28,7 @@
 BLACK_PATHS = ["docs", "google_auth_oauthlib", "tests", "noxfile.py", "setup.py"]
 
 DEFAULT_PYTHON_VERSION = "3.8"
-SYSTEM_TEST_PYTHON_VERSIONS = ["2.7", "3.8"]
+SYSTEM_TEST_PYTHON_VERSIONS = ["3.8"]
 UNIT_TEST_PYTHON_VERSIONS = ["3.6", "3.7", "3.8", "3.9"]
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
@@ -84,6 +84,8 @@ def default(session):
     constraints_path = str(
         CURRENT_DIRECTORY / "testing" / f"constraints-{session.python}.txt"
     )
+    session.install("asyncmock", "pytest-asyncio", "-c", constraints_path)
+
     session.install("mock", "pytest", "pytest-cov", "click", "-c", constraints_path)
 
     session.install("-e", ".", "-c", constraints_path)

owlbot.py

@@ -7,6 +7,7 @@
 # Add templated files
 # ----------------------------------------------------------------------------
 templated_files = common.py_library(
+    microgenerator=True,
     cov_level=99,
     unit_test_external_dependencies=["click"],
     unit_test_python_versions=["3.6", "3.7", "3.8", "3.9"],