diff --git a/aio/README.md b/aio/README.md
index dde1c957d9..4a183af8cd 100644
--- a/aio/README.md
+++ b/aio/README.md
@@ -22,7 +22,8 @@ Here are the most important tasks you might need to use:
 * `yarn start` - run a development web server that watches the files; then builds the doc-viewer and reloads the page, as necessary.
 * `yarn serve-and-sync` - run both the `docs-watch` and `start` in the same console.
 * `yarn lint` - check that the doc-viewer code follows our style rules.
-* `yarn test` - watch all the source files, for the doc-viewer, and run all the unit tests when any change.
+* `yarn test` - run all the unit tests once.
+* `yarn test --watch` - watch all the source files, for the doc-viewer, and run all the unit tests when any change.
 * `yarn e2e` - run all the e2e tests for the doc-viewer.
 
 * `yarn docs` - generate all the docs from the source files.