This test requires three Google accounts, one for the site, one for the student and one for the teacher.

Note: It is important to log out of all Google accounts between the different stages in this test otherwise Google will open the document using whatever is the first account in the list of accounts, and even if you have edit access for another account it will appear read-only until you switch users.

1. Log in as an admin and set up and configure the OAuth 2 Google service with a client ID and secret, as described in the documentation OAuth2 Services and OAuth 2 Google service.
2. Enable the OAuth2 authentication plugin.
3. Enable the Google Drive repository, making sure it is connected to the Google service.
4. Set the supported files to "Internal and External".
5. Set the "Default return type" to "External (only links stored in Moodle)".
6. Go again to the OAuth2 services page, connect the account to a site Google account and consent the access to Google drive.
7. Edit the default teacher role permissions and add the capability "mod/assign:editothersubmission".
8. As a teacher, create an assignment requiring a file upload.
9. Log out of all Google accounts.
10. Log in as a student, select a document from your Google account and select 'Create an access controlled link to the file'.
11. Log out of all Google accounts.
12. Log in as the teacher. Access the assignment. Click on the link. Verify that you are prompted to log in to your Google account.
13. Log in with a different account than the one used to upload the student's submission. Verify you can edit the student's document.
14. Make some changes, such as adding text, to the student's document.
15. Log out of all Google accounts.
16. Log in as the student, access your assignment and verify you see the changes that the teacher made in the returned Google doc. Note that it is not yet possible for a student to see any comments that the teacher made (MDL-58831).
17. As the student, go to your personal Google drive and verify the original document has not been altered.