What is the test for the doctrine of estoppel?

In the case of Ryan v. Moore [2005] S.C.R. 38, the court stated the following at paragraph 59: This court is not bound by any of the above analytical framework. After having reviewed the jurisprudence in the United Kingdom and Canada as well as academic comments on the subject, I am of the view that the following criteria form the basis of the doctrine of estoppel by convention: 1) The parties dealings must have been based on a shared assumption of fact or law: estoppel requires manifest representation by statement or conduct creating a mutual assumption. Nevertheless, estoppel can arise out of silence (impliedly). 2) A party must have conducted itself, i.e. acted, in reliance on such shared assumption, its actions resulting in a change of its legal position. 3) It must also be unjust or unfair to allow one of the parties to resile or depart from the common assumption. The party seeking to establish estoppel therefore has to prove that detriment will be suffered in the other party is allowed to resile from the assumption since there has been a change from the presumed position.