public void When_a_template_containing_a_user_token_is_formatted_then_the_user_token_is_replaced_with_the_users_name() { var user = Mock.Of <IUser>(); Mock.Get(user) .Setup(x => x.DisplayName) .Returns("you"); var result = TestInstance.FormatMessage( user, $"Hi {CookieMessageTokens.USER_DISPLAY_NAME}!"); result.ShouldBe("Hi you!"); }