envoyproxy · alyssawilk · Jan 13, 2021 · Jan 13, 2021 · Jan 13, 2021
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -99,7 +99,7 @@ versioning guidelines:
 
  Please see [support/README.md](support/README.md) for more information on these hooks.
 
-* Create your PR.
+* Create your PR. If your PR adds new code, it should include tests [covering](source/docs/coverage.md) the new code.
 * Tests will automatically run for you.
 * We will **not** merge any PR that is not passing tests.
 * PRs are expected to have 100% test coverage for added code. This can be verified with a coverage

diff --git a/source/docs/aclick.png b/source/docs/aclick.png
diff --git a/source/docs/click.png b/source/docs/click.png
diff --git a/source/docs/coverage.md b/source/docs/coverage.md
@@ -0,0 +1,49 @@
+### How can I tell if my new code is covered by tests?
+
+In a PR run, for example https://github.com/envoyproxy/envoy/pull/14672
+
+Click on the check mark or X for the CI results you want to look at. Generally
+this will be the last run, but for this example we’ll pick an earlier, failed
+run.
+
+![PR view](pr_view.png)
+
+Next, click on the “Details” link on the coverage run. If the run was a success
+you may need to scroll down to see the coverage build.
+
+![click coverage](click.png)
+
+Next up, click on the warnings/errors link. For a successful coverage run, this will list zero errors/warnings but will still be clickable
+
+![click error](eclick.png)
+
+On the azure results page, again click through to see results.
+
+![azure error](aclick.png)
+
+![coverage results](results.png)
+
+
+In this case the error reason was clear, and the directory missing coverage is listed. To get an understanding of what lines aren’t covered, you can browse further.
+
+Scroll down on the left, and click on “Upload coverage reports”
+This will provide a link on the right, telling you where the coverage
+upload went, in this case a link to
+“https://storage.googleapis.com/envoy-pr/269d783/coverage/index.html” (which
+will only be valid for some number of days). 
+
+![coverage upload](upload.png)
+
+Clicking on the link provides a full color-annotated coverage report
+
+![coverage report](report.png)
+
+You can browse this report to the directory in question. In this particular
+case the coverage issue was actually a coverage bug, where trailing braces in
+tested switch statements are considered uncovered lines. Generally this will
+instead provide a branch of code which simply needs unit tests.
+
+![coverage file](file.png)
+
+
+
diff --git a/source/docs/eclick.png b/source/docs/eclick.png
diff --git a/source/docs/file.png b/source/docs/file.png
diff --git a/source/docs/pr_view.png b/source/docs/pr_view.png
diff --git a/source/docs/report.png b/source/docs/report.png
diff --git a/source/docs/results.png b/source/docs/results.png
diff --git a/source/docs/upload.png b/source/docs/upload.png