refactoring service discovery and load balancing approach into load balancing middleware

test/Ocelot.UnitTests/ServiceDiscovery/ConfigurationServiceProviderTests.cs

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+using System.Collections.Generic;
+using Ocelot.ServiceDiscovery;
+using Ocelot.Values;
+using Shouldly;
+using TestStack.BDDfy;
+using Xunit;
+
+namespace Ocelot.UnitTests.ServiceDiscovery
+{
+    public class ConfigurationServiceProviderTests
+    {
+        private ConfigurationServiceProvider _serviceProvider;
+        private HostAndPort _hostAndPort;
+        private List<Service> _result;
+        private List<Service> _expected;
+
+        [Fact]
+        public void should_return_services()
+        {
+            var hostAndPort = new HostAndPort("127.0.0.1", 80);
+
+            var services = new List<Service>
+            {
+                new Service("product", hostAndPort)
+            };
+
+            this.Given(x => x.GivenServices(services))
+                .When(x => x.WhenIGetTheService())
+                .Then(x => x.ThenTheFollowingIsReturned(services))
+                .BDDfy();
+        }
+
+        private void GivenServices(List<Service> services)
+        {
+            _expected = services;
+        }
+
+        private void WhenIGetTheService()
+        {
+            _serviceProvider = new ConfigurationServiceProvider(_expected);
+            _result = _serviceProvider.Get();
+        }
+
+        private void ThenTheFollowingIsReturned(List<Service> services)
+        {
+            _result[0].HostAndPort.DownstreamHost.ShouldBe(services[0].HostAndPort.DownstreamHost);
+
+            _result[0].HostAndPort.DownstreamPort.ShouldBe(services[0].HostAndPort.DownstreamPort);
+
+            _result[0].Name.ShouldBe(services[0].Name);
+        }
+    }
+}

test/Ocelot.UnitTests/ServiceDiscovery/ServiceProviderFactoryTests.cs

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+using Ocelot.ServiceDiscovery;
+using Shouldly;
+using TestStack.BDDfy;
+using Xunit;
+
+namespace Ocelot.UnitTests.ServiceDiscovery
+{
+    public class ServiceProviderFactoryTests
+    {
+        private ServiceConfiguraion _serviceConfig;
+        private IServiceProvider _result;
+        private readonly ServiceProviderFactory _factory;
+
+        public ServiceProviderFactoryTests()
+        {
+            _factory = new ServiceProviderFactory();
+        }
+        
+        [Fact]
+        public void should_return_no_service_provider()
+        {
+            var serviceConfig = new ServiceConfiguraion("product", "127.0.0.1", 80, false);
+
+            this.Given(x => x.GivenTheReRoute(serviceConfig))
+                .When(x => x.WhenIGetTheServiceProvider())
+                .Then(x => x.ThenTheServiceProviderIs<ConfigurationServiceProvider>())
+                .BDDfy();
+        }
+
+        private void GivenTheReRoute(ServiceConfiguraion serviceConfig)
+        {
+            _serviceConfig = serviceConfig;
+        }
+
+        private void WhenIGetTheServiceProvider()
+        {
+            _result = _factory.Get(_serviceConfig);
+        }
+
+        private void ThenTheServiceProviderIs<T>()
+        {
+            _result.ShouldBeOfType<T>();
+        }
+    }
+}

test/Ocelot.UnitTests/ServiceDiscovery/ServiceRegistryTests.cs

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+using System.Collections.Generic;
+using Ocelot.Values;
+using Shouldly;
+using TestStack.BDDfy;
+using Xunit;
+
+namespace Ocelot.UnitTests.ServiceDiscovery
+{
+    public class ServiceRegistryTests
+    {
+        private Service _service;
+        private List<Service> _services;
+        private ServiceRegistry _serviceRegistry;
+        private ServiceRepository _serviceRepository;
+
+        public ServiceRegistryTests()
+        {
+            _serviceRepository = new ServiceRepository();
+            _serviceRegistry = new ServiceRegistry(_serviceRepository);
+        }
+
+        [Fact]
+        public void should_register_service()
+        {
+            this.Given(x => x.GivenAServiceToRegister("product", "localhost:5000", 80))
+            .When(x => x.WhenIRegisterTheService())
+            .Then(x => x.ThenTheServiceIsRegistered())
+            .BDDfy();
+        }
+
+        public void should_lookup_service()
+        {
+            this.Given(x => x.GivenAServiceIsRegistered("product", "localhost:600", 80))
+            .When(x => x.WhenILookupTheService("product"))
+            .Then(x => x.ThenTheServiceDetailsAreReturned())
+            .BDDfy();
+        }
+
+        private void ThenTheServiceDetailsAreReturned()
+        {
+            _services[0].HostAndPort.DownstreamHost.ShouldBe(_service.HostAndPort.DownstreamHost);
+            _services[0].HostAndPort.DownstreamPort.ShouldBe(_service.HostAndPort.DownstreamPort);
+            _services[0].Name.ShouldBe(_service.Name);
+        }
+
+        private void WhenILookupTheService(string name)
+        {
+            _services = _serviceRegistry.Lookup(name);
+        }
+
+        private void GivenAServiceIsRegistered(string name, string address, int port)
+        {
+            _service = new Service(name, new HostAndPort(address, port));
+            _serviceRepository.Set(_service);
+        }
+
+        private void GivenAServiceToRegister(string name, string address, int port)
+        {
+            _service = new Service(name, new HostAndPort(address, port));
+        }
+
+        private void WhenIRegisterTheService()
+        {
+            _serviceRegistry.Register(_service);
+        }
+
+        private void ThenTheServiceIsRegistered()
+        {
+            var serviceNameAndAddress = _serviceRepository.Get(_service.Name);
+            serviceNameAndAddress[0].HostAndPort.DownstreamHost.ShouldBe(_service.HostAndPort.DownstreamHost);
+            serviceNameAndAddress[0].HostAndPort.DownstreamPort.ShouldBe(_service.HostAndPort.DownstreamPort);
+            serviceNameAndAddress[0].Name.ShouldBe(_service.Name);
+        }
+    }
+
+    public interface IServiceRegistry
+    {
+        void Register(Service serviceNameAndAddress);
+        List<Service> Lookup(string name);
+    }
+
+    public class ServiceRegistry : IServiceRegistry
+    {
+        private readonly IServiceRepository _repository;
+        public ServiceRegistry(IServiceRepository repository)
+        {
+            _repository = repository;
+        }   
+
+        public void Register(Service serviceNameAndAddress)
+        {
+            _repository.Set(serviceNameAndAddress);
+        }
+
+        public List<Service> Lookup(string name)
+        {
+            return _repository.Get(name);
+        }
+    }
+
+    public interface IServiceRepository
+    {
+        List<Service> Get(string serviceName);
+        void Set(Service serviceNameAndAddress);
+    }
+
+    public class ServiceRepository : IServiceRepository
+    {
+        private Dictionary<string, List<Service>> _registeredServices;
+
+        public ServiceRepository()
+        {
+            _registeredServices = new Dictionary<string, List<Service>>();
+        }
+
+        public List<Service> Get(string serviceName)
+        {
+            return _registeredServices[serviceName];
+        }
+
+        public void Set(Service serviceNameAndAddress)
+        {
+            List<Service> services;
+            if(_registeredServices.TryGetValue(serviceNameAndAddress.Name, out services))
+            {
+                services.Add(serviceNameAndAddress);
+                _registeredServices[serviceNameAndAddress.Name] = services;
+            }
+            else
+            {     
+                _registeredServices[serviceNameAndAddress.Name] = new List<Service>(){ serviceNameAndAddress };
+            }
+            
+        }
+    }
+}