First follow the directions to acquire the necessary credentials.
Then continue below to configure and run the TestSharepointImpl test case using them.
The io.github.sharepoint_oauth.SharepointImpl class acquires a token which can be used to make requests to sharepoint.
The SharepointAPI exposes some methods for file operations based on the REST API methods described here: https://docs.microsoft.com/en-us/sharepoint/dev/sp-add-ins/working-with-folders-and-files-with-rest
You could adjust the api to support other methods and file a pull request.
Change line 43 in TestSharepointImpl to setup the url to your sharepoint site (must be the same site used when setting up the credentials):
sharepoint.setSharepointBaseUrl("https://mycompany.sharepoint.com/sites/my-site/_api/web");
Setup system properties to pass through the actual sharepoint credentials:
-Dclient_id=AAAAAAAA-AAAA-AAAA-AAAA-AAAAAAAAAAAA/localhost@11111111-2222-2222-3333-333333333333
-Dclient_secret=QSBjbGllbnQgc2VjcmV0IHdvdWxkIGJlIGhlcmUgaW4gcmVhbCBsaWZl
-Dresource=11111111-1111-1111-1111-12345678900/mycompany.sharepoint.com@11111111-2222-2222-3333-333333333333
After running the test case then you can expect two files to have been placed into the root of the Shared Documents of your Sharepoint Site: