When FormulaShareSObjectShares attempts to insert sharing in a test context when this is called via the async (batch) method, Salesforce does not respect the permission set applied to the test user. Running under a system administrator profile allows these inserts to go ahead but we can't guarantee this exists with consistent settings in every org.
To avoid complications FormulaShareSObjectShares should be mocked in any test DML carried out in async context
When FormulaShareSObjectShares attempts to insert sharing in a test context when this is called via the async (batch) method, Salesforce does not respect the permission set applied to the test user. Running under a system administrator profile allows these inserts to go ahead but we can't guarantee this exists with consistent settings in every org.
To avoid complications FormulaShareSObjectShares should be mocked in any test DML carried out in async context