The test expects an empty StartApplyingDonorOpTime. But the test doesn't have a failpoint to block the future chain from getting one and this could race with the this onReceiveRecipientForgetMigration. If the interruption from the recipientForgetMigration gets in before the future chain calling _getStartOpTimesFromDonor, the test will pass. However, if the interrupt gets in after that, the state doc could have a StartApplyingDonorOpTime and/or StartFetchingDonorOpTime. Additionally, if the interrupt comes after the cloners have started, the test is also missing mock responses for the requests coming from the donors.

The test is only testing that onReceiveRecipientForgetMigration must wait until the state doc is initialized. So we don't have to have the chain run beyond fpAfterPersistingTenantMigrationRecipientInstanceStateDoc. Therefore, adding a failpoint will fix this.