Add testing functionality for DOI metadata retrieval and saving

[chartgerink]

We sometimes/regularly get reports of DOIs whose metadata cannot be retrieved. It would be great for us to write a test to ensure our fixes don't regress in the future.

This issue requires documentation before continuing work.

We will need to identify the relevant code where metadata is retrieved, before we can add the test. This is a great opportunity to evaluate whether that code is in the good shape for testing as well.

List of DOIs

https://doi.org/10.1007/978-3-031-17037-9_4

[github-actions]

This issue is stale because it has been open 60 days with no activity.