public void GetNextRelationByExpertName_CurrentSessionExist_GetFromExpertService()
        {
            var serviceUnderTest = CreateServiceUnderTest();
            var session          = SetFakeSession();
            var expertName       = "expertTest";

            var relationPair = new Tuple <Relation, Relation>(
                Substitute.For <Relation>(),
                Substitute.For <Relation>());

            _fakeExpertService.GetNextRelationPairByExpertNameAndSession(Arg.Is(expertName), Arg.Is(session))
            .Returns(relationPair);

            var result = serviceUnderTest.GetNextRelationByExpertName(expertName);

            Assert.AreSame(relationPair, result);
        }