Add frontend tests to docs

docs/extending.rst

@@ -34,6 +34,8 @@ it fixed for everyone!
 Before contributing please review our `code of conduct`_ and other important
 information in the `contributing guidelines`_.
 
+.. _code-formatting-with-pre-commit-hooks:
+
 Code formatting with pre-commit Hooks
 =====================================
 
@@ -183,6 +185,31 @@ X-Frame-Options are in place so that the front end behaves exactly as in product
 relies on you being logged into the back end. Without a valid session, The front end will simply
 not work.
 
+Testing and code style:
+
+*   The frontend code (.ts, .html, .scss) use ``prettier`` for code formatting via the Git
+    ``pre-commit`` hooks which run automatically on commit. See
+    :ref:`above <code-formatting-with-pre-commit-hooks>` for installation. You can also run this
+    via cli with a command such as
+
+    .. code:: shell-session
+
+        $ git ls-files -- '*.ts' | xargs pre-commit run prettier --files
+
+*   Frontend testing uses jest and cypress. There is currently a need for significantly more
+    frontend tests. Unit tests and e2e tests, respectively, can be run non-interactively with:
+
+    .. code:: shell-session
+
+        $ ng test
+        $ npm run e2e:ci
+
+    Cypress also includes a UI which can be run from within the ``src-ui`` directory with
+
+    .. code:: shell-session
+
+        $ ./node_modules/.bin/cypress open
+
 In order to build the front end and serve it as part of django, execute
 
 .. code:: shell-session