chore: fix kokoro config for samples (#227)

Source-Link: googleapis/synthtool@dd05f9d
Post-Processor: gcr.io/repo-automation-bots/owlbot-python:latest@sha256:aea14a583128771ae8aefa364e1652f3c56070168ef31beb203534222d842b8b

Author: gcf-owl-bot[bot]

packages/sqlalchemy-bigquery/.github/.OwlBot.lock.yaml

@@ -1,3 +1,3 @@
 docker:
   image: gcr.io/repo-automation-bots/owlbot-python:latest
-  digest: sha256:5ff7446edeaede81c3ed58b23a4e76a5403fba1350ce28478045657303b6479d
+  digest: sha256:aea14a583128771ae8aefa364e1652f3c56070168ef31beb203534222d842b8b

packages/sqlalchemy-bigquery/.kokoro/samples/python3.6/periodic-head.cfg

@@ -7,5 +7,5 @@ env_vars: {
 
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
-    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+    value: "github/python-bigquery-sqlalchemy/.kokoro/test-samples-against-head.sh"
 }

packages/sqlalchemy-bigquery/.kokoro/samples/python3.7/periodic-head.cfg

@@ -7,5 +7,5 @@ env_vars: {
 
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
-    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+    value: "github/python-bigquery-sqlalchemy/.kokoro/test-samples-against-head.sh"
 }

packages/sqlalchemy-bigquery/.kokoro/samples/python3.8/periodic-head.cfg

@@ -7,5 +7,5 @@ env_vars: {
 
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
-    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+    value: "github/python-bigquery-sqlalchemy/.kokoro/test-samples-against-head.sh"
 }

packages/sqlalchemy-bigquery/.kokoro/samples/python3.9/periodic-head.cfg

@@ -7,5 +7,5 @@ env_vars: {
 
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
-    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+    value: "github/python-bigquery-sqlalchemy/.kokoro/test-samples-against-head.sh"
 }

packages/sqlalchemy-bigquery/CONTRIBUTING.rst

@@ -177,6 +177,30 @@ Build the docs via:
 
    $ nox -s docs
 
+*************************
+Samples and code snippets
+*************************
+
+Code samples and snippets live in the `samples/` catalogue. Feel free to
+provide more examples, but make sure to write tests for those examples.
+Each folder containing example code requires its own `noxfile.py` script
+which automates testing. If you decide to create a new folder, you can
+base it on the `samples/snippets` folder (providing `noxfile.py` and
+the requirements files).
+
+The tests will run against a real Google Cloud Project, so you should
+configure them just like the System Tests.
+
+- To run sample tests, you can execute::
+
+   # Run all tests in a folder
+   $ cd samples/snippets
+   $ nox -s py-3.8
+
+   # Run a single sample test
+   $ cd samples/snippets
+   $ nox -s py-3.8 -- -k <name of test>
+
 ********************************************
 Note About ``README`` as it pertains to PyPI
 ********************************************