What is the test for common interest privilege?

More generally, Ricchetti J. (as he then was) identified the test for common interest privilege in Milicevic v. T Smith Engineering Limited 2016 ONSC 2166 as requiring the following three conditions to be met (see para. 137): a) That the communication is subject to solicitor-client privilege or litigation privilege; and b) That the party with whom the communication was shared with or originated from has a common objective or interest with the party who has solicitor-client privilege over the communication; and c) That the privilege has not been lost through waiver, disclosure or otherwise at law by or with the consent of the parties who hold privilege over the document(s).