gast: improve api coverage

[serge-sans-paille]

Test basic api
Test basic invariant

[github-actions]

serge-sans-paille is a new contributor to projects/gast. The PR must be approved by known contributors before it can be merged.

[serge-sans-paille]

cc @AdamKorcz as you validated the initial integration

[serge-sans-paille]

@AdamKorcz looks good now? I've also merged a fix for one of the failure detected by the API in upstream gast

[serge-sans-paille]

Also cc @DavidKorczynski who did the initial integration.
As a side note, I'm the actual developper of gast ^^!

[DavidKorczynski]

Also cc @DavidKorczynski who did the initial integration. As a side note, I'm the actual developper of gast ^^!

Thanks @serge-sans-paille ! That's great! We'd be very happy if you can take charge of the integration -- feel free to migrate fuzzers to upstream and also feel free to update the project.yaml so you're listed as the primary_contact. And feel free to remove me under the vendor_ccs.

[serge-sans-paille]

Thanks @DavidKorczynski . yeah, I plan to head that way, but beforehand I need to get myself used to oss-fuzz.
For instance I don't understand the failure in coverage information retrieval in https://introspector.oss-fuzz.com/project-profile?project=gast