Enable tenant management tests for releases. (#740)

Also document how to enable these tests in the CONTRIBUTING.md file.

Author: bojeil-google

CONTRIBUTING.md

@@ -183,6 +183,21 @@ integration tests can pass, launch the tests as follows:
 $ npm run test:integration -- --updateRules
 ```
 
+The integration test suite skips the multi-tenancy Auth tests by default.
+If you want to run these tests, an
+[Identity Platform](https://cloud.google.com/identity-platform/) project with multi-tenancy
+[enabled](https://cloud.google.com/identity-platform/docs/multi-tenancy-quickstart#enabling_multi-tenancy)
+will be required.
+An existing Firebase project can be upgraded to an Identity Platform project without
+losing any functionality via the
+[Identity Platform Marketplace Page](https://console.cloud.google.com/customer-identity).
+Note that charges may be incurred for active users beyond the Identity Platform free tier.
+The integration tests can be launched with these tests enabled as follows:
+
+```bash
+$ npm run test:integration -- --testMultiTenancy
+```
+
 ### Repo Organization
 
 Here are some highlights of the directory structure and notable source files

createReleaseTarball.sh

@@ -137,7 +137,7 @@ fi
 echo
 
 echo "[INFO] Running integration tests..."
-npm run test:integration -- --updateRules
+npm run test:integration -- --updateRules --testMultiTenancy
 if [[ $? -ne 0 ]]; then
   echo "Error: Integration tests failed."
   exit 1