docs: Document how to run system tests against the emulator. (#963)

sorced-jim · web-flow · commit 47db5b9f6ee1 · 2024-03-08T12:58:57.000-08:00
diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
@@ -158,6 +158,9 @@ Running System Tests
   auth settings and change some configuration in your project to
   run all the tests.
 
+- System tests may be run against the emulator. To do this, set the
+  ``DATASTORE_EMULATOR_HOST`` environment variable.
+
 - System tests will be run against an actual project and
   so you'll need to provide some environment variables to facilitate
   authentication to your project:
