chore: Update integration test project setup instructions. (#877)

* Update integration test project setup instructions.

* fix: remove duplicate

* fix: addresses some of the code review notes

* fix: addresses remaining code review notes and some typos

* Add note on 2nd rtdb reference.

* fix: nits

* fix: pencil

* Added service account management note.

Author: jonathanedey

CONTRIBUTING.md

@@ -127,27 +127,90 @@ mvn test
 Integration tests are also written using Junit4. They coexist with the unit tests in the `src/test`
 subdirectory. Integration tests follow the naming convention `*IT.java` (e.g. `DataTestIT.java`),
 which enables the Maven Surefire and Failsafe plugins to differentiate between the two types of
-tests. Integration tests are executed against a real life Firebase project, and therefore
-requires an Internet connection.
-
-Create a new project in the [Firebase console](https://console.firebase.google.com/) if you do
-not already have one. Use a separate, dedicated project for integration tests since the test suite
-makes a large number of writes to the Firebase realtime database. Download the service account
-private key from the "Settings > Service Accounts" page of the project, and save it as
-`integration_cert.json` at the root of the codebase. Grant your service account the `Firebase
-Authentication Admin` role at
-[Google Cloud Platform Console / IAM & admin](https://console.cloud.google.com/iam-admin). This is
-required to ensure that exported user records contain the password hashes of the user accounts.
-Also obtain the web API key of the project from the "Settings > General" page, and save it as
-`integration_apikey.txt` at the root of the codebase.
-
-Some of the integration tests require 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).
-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.
+tests.
+
+Integration tests are executed against a real life Firebase project. If you do not already
+have one suitable for running the tests against, you can create a new project in the
+[Firebase Console](https://console.firebase.google.com) following the setup guide below.
+If you already have a Firebase project, you'll need to obtain credentials to communicate and
+authorize access to your Firebase project:
+
+1. Service account certificate: This allows access to your Firebase project through a service account
+which is required for all integration tests. This can be downloaded as a JSON file from the 
+**Settings > Service Accounts** tab of the Firebase console when you click the
+**Generate new private key** button. Copy the file into the repo so it's available at
+`integration_cert.json`.
+   > **Note:** Service accounts should be carefully managed and their keys should never be stored in publicly accessible source code or repositories.
+
+
+2. Web API key: This allows for Auth sign-in needed for some Authentication and Tenant Management
+integration tests. This is displayed in the **Settings > General** tab of the Firebase console
+after enabling Authentication as described in the steps below. Copy it and save to a new text
+file at `integration_apikey.txt`.
+
+
+Set up your Firebase project as follows:
+
+
+1. Enable Authentication:
+   1. Go to the Firebase Console, and select **Authentication** from the **Build** menu.
+   2. Click on **Get Started**.
+   3. Select **Sign-in method > Add new provider > Email/Password** then enable both the
+   **Email/Password** and **Email link (passwordless sign-in)** options.
+
+
+2. Enable Firestore:
+   1. Go to the Firebase Console, and select **Firestore Database** from the **Build** menu.
+   2. Click on the **Create database** button. You can choose to set up Firestore either in
+   the production mode or in the test mode.
+
+
+3. Enable Realtime Database:
+   1. Go to the Firebase Console, and select **Realtime Database** from the **Build** menu.
+   2. Click on the **Create Database** button. You can choose to set up the Realtime Database
+   either in the locked mode or in the test mode.
+
+   > **Note:** Integration tests are not run against the default Realtime Database reference and are
+   instead run against a database created at `https://{PROJECT_ID}.firebaseio.com`.
+   This second Realtime Database reference is created in the following steps.
+
+   3. In the **Data** tab click on the kebab menu (3 dots) and select **Create Database**.
+   4. Enter your Project ID (Found in the **General** tab in **Account Settings**) as the
+   **Realtime Database reference**. Again, you can choose to set up the Realtime Database
+   either in the locked mode or in the test mode.
+
+
+4. Enable Storage:
+   1. Go to the Firebase Console, and select **Storage** from the **Build** menu.
+   2. Click on the **Get started** button. You can choose to set up Cloud Storage
+   either in the production mode or in the test mode.
+
+
+5. Enable the IAM API:
+   1. Go to the [Google Cloud console](https://console.cloud.google.com)
+   and make sure your Firebase project is selected.
+   2. Select **APIs & Services** from the main menu, and click the
+   **ENABLE APIS AND SERVICES** button.
+   3. Search for and enable **Identity and Access Management (IAM) API** by Google Enterprise API.
+
+
+6. Enable Tenant Management:
+   1. Go to
+   [Google Cloud console | Identity Platform](https://console.cloud.google.com/customer-identity/)
+   and if it is not already enabled, click **Enable**.
+   2. Then
+   [enable multi-tenancy](https://cloud.google.com/identity-platform/docs/multi-tenancy-quickstart#enabling_multi-tenancy)
+   for your project.
+
+
+7. Ensure your service account has the **Firebase Authentication Admin** role. This is required
+to ensure that exported user records contain the password hashes of the user accounts:
+   1. Go to [Google Cloud console | IAM & admin](https://console.cloud.google.com/iam-admin).
+   2. Find your service account in the list. If not added click the pencil icon to edit its
+   permissions.
+   3. Click **ADD ANOTHER ROLE** and choose **Firebase Authentication Admin**.
+   4. Click **SAVE**.
+
 
 Now run the following command to invoke the integration test suite: