public void SuccessMatch()
        {
            // Arrange
            var validatorFactory = new Mock <IValidatorEngine>();
            var mappingEngine    = new Mock <IMappingEngine>();
            var repository       = new Mock <IRepository>();
            var searchCache      = new Mock <ISearchCache>();

            var service = new SourceSystemService(validatorFactory.Object, mappingEngine.Object, repository.Object, searchCache.Object);

            // Domain details
            var system = new Mdm.SourceSystem {
                Name = "Endur"
            };
            var mapping = new SourceSystemMapping
            {
                System       = system,
                MappingValue = "A"
            };
            var targetSystem = new Mdm.SourceSystem {
                Name = "Trayport"
            };
            var targetMapping = new SourceSystemMapping
            {
                System       = targetSystem,
                MappingValue = "B",
                IsDefault    = true
            };
            var sourcesystem = new Mdm.SourceSystem
            {
                Id        = 1,
                Timestamp = new byte[] { 1, 0, 0, 0, 0, 0, 0, 0 }
            };

            //SourceSystem.AddDetails(details);
            sourcesystem.ProcessMapping(mapping);
            sourcesystem.ProcessMapping(targetMapping);

            // Contract details
            var targetIdentifier = new MdmId
            {
                SystemName = "Trayport",
                Identifier = "B"
            };

            mappingEngine.Setup(x => x.Map <SourceSystemMapping, MdmId>(targetMapping)).Returns(targetIdentifier);

            var list = new List <SourceSystemMapping> {
                mapping
            };

            repository.Setup(x => x.Queryable <SourceSystemMapping>()).Returns(list.AsQueryable());

            var request = new CrossMappingRequest
            {
                SystemName       = "Endur",
                Identifier       = "A",
                TargetSystemName = "trayport",
                ValidAt          = SystemTime.UtcNow(),
                Version          = 0
            };

            // Act
            var response  = service.CrossMap(request);
            var candidate = response.Contract;

            // Assert
            Assert.IsNotNull(response, "Contract null");
            Assert.IsNotNull(candidate, "Mapping null");
            Assert.AreEqual(1, candidate.Mappings.Count, "Identifier count incorrect");
            Assert.AreSame(targetIdentifier, candidate.Mappings[0], "Different identifier assigned");
        }