Test incomplete reports

Summary:
Provide 4 flavours of report: full, empty, no metadata, only metadata.

That allows to test code robustness when any part is missing.

Test Plan:
Provide new tests. They pass for full report and fail for the others.

This change is only to provide tests, follow-up changes will fix code.

Reviewers: DorianWinty

Reviewed By: DorianWinty

Differential Revision: https://devcentral.nasqueron.org/D2537