diff --git a/src/Microsoft.AspNetCore.Hosting.Abstractions/HostingAbstractionsWebHostBuilderExtensions.cs b/src/Microsoft.AspNetCore.Hosting.Abstractions/HostingAbstractionsWebHostBuilderExtensions.cs
index c98de63e..a2bca308 100644
--- a/src/Microsoft.AspNetCore.Hosting.Abstractions/HostingAbstractionsWebHostBuilderExtensions.cs
+++ b/src/Microsoft.AspNetCore.Hosting.Abstractions/HostingAbstractionsWebHostBuilderExtensions.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Linq;
 using System.Threading;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.Hosting.Server;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
@@ -58,8 +57,8 @@ public static IWebHostBuilder UseStartup(this IWebHostBuilder hostBuilder, strin
 
 
             return hostBuilder
-                    .UseSetting(WebHostDefaults.ApplicationKey, startupAssemblyName)
-                    .UseSetting(WebHostDefaults.StartupAssemblyKey, startupAssemblyName);
+                .UseSetting(WebHostDefaults.ApplicationKey, startupAssemblyName)
+                .UseSetting(WebHostDefaults.StartupAssemblyKey, startupAssemblyName);
         }
 
         /// <summary>
diff --git a/src/Microsoft.AspNetCore.Hosting.Abstractions/IWebHostBuilder.cs b/src/Microsoft.AspNetCore.Hosting.Abstractions/IWebHostBuilder.cs
index 013cda5c..c22c2edb 100644
--- a/src/Microsoft.AspNetCore.Hosting.Abstractions/IWebHostBuilder.cs
+++ b/src/Microsoft.AspNetCore.Hosting.Abstractions/IWebHostBuilder.cs
@@ -27,13 +27,15 @@ public interface IWebHostBuilder
         /// </summary>
         IWebHost Build();
 
-        // TODO: update these doc comments to indicate what may be null during configuration.
-
         /// <summary>
         /// Adds a delegate for configuring the <see cref="IConfigurationBuilder"/> that will construct an <see cref="IConfiguration"/>.
         /// </summary>
         /// <param name="configureDelegate">The delegate for configuring the <see cref="IConfigurationBuilder" /> that will be used to construct an <see cref="IConfiguration" />.</param>
         /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
+        /// <remarks>
+        /// The <see cref="IConfiguration"/> and <see cref="ILoggerFactory"/> on the <see cref="WebHostBuilderContext"/> are uninitialized at this stage.
+        /// The <see cref="IConfigurationBuilder"/> is pre-populated with the settings of the <see cref="IWebHostBuilder"/>.
+        /// </remarks>
         IWebHostBuilder ConfigureAppConfiguration(Action<WebHostBuilderContext, IConfigurationBuilder> configureDelegate);
 
         /// <summary>
@@ -47,20 +49,29 @@ public interface IWebHostBuilder
         /// Adds a delegate for configuring the provided <see cref="ILoggerFactory"/>. This may be called multiple times.
         /// </summary>
         /// <param name="configureLogging">The delegate that configures the <see cref="ILoggerFactory"/>.</param>
+        /// <typeparam name="T">
+        /// The type of <see cref="ILoggerFactory"/> to configure.
+        /// The delegate will not execute if the type provided does not match the <see cref="ILoggerFactory"/> used by the <see cref="IWebHostBuilder"/>
+        /// </typeparam>
         /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
+        /// <remarks>
+        /// The <see cref="ILoggerFactory"/> on the <see cref="WebHostBuilderContext"/> is uninitialized at this stage.
+        /// </remarks>
         IWebHostBuilder ConfigureLogging<T>(Action<WebHostBuilderContext, T> configureLogging) where T : ILoggerFactory;
 
         /// <summary>
-        /// Specify the delegate that is used to configure the services of the web application.
+        /// Adds a delegate for configuring additional services for the host or web application. This may be called
+        /// multiple times.
         /// </summary>
-        /// <param name="configureServices">The delegate that configures the <see cref="IServiceCollection"/>.</param>
+        /// <param name="configureServices">A delegate for configuring the <see cref="IServiceCollection"/>.</param>
         /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
         IWebHostBuilder ConfigureServices(Action<IServiceCollection> configureServices);
 
         /// <summary>
-        /// Specify the delegate that is used to configure the services of the web application.
+        /// Adds a delegate for configuring additional services for the host or web application. This may be called
+        /// multiple times.
         /// </summary>
-        /// <param name="configureServices">The delegate that configures the <see cref="IServiceCollection"/>.</param>
+        /// <param name="configureServices">A delegate for configuring the <see cref="IServiceCollection"/>.</param>
         /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
         IWebHostBuilder ConfigureServices(Action<WebHostBuilderContext, IServiceCollection> configureServices);
 
@@ -92,6 +103,9 @@ public interface IWebHostBuilder
         /// </summary>
         /// <param name="createLoggerFactory">The delegate that constructs an <see cref="IConfigurationBuilder" /></param>
         /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
+        /// <remarks>
+        /// The <see cref="ILoggerFactory"/> on the <see cref="WebHostBuilderContext"/> is uninitialized at this stage.
+        /// </remarks>
         IWebHostBuilder UseLoggerFactory(Func<WebHostBuilderContext, ILoggerFactory> createLoggerFactory);
     }
 }
\ No newline at end of file
diff --git a/src/Microsoft.AspNetCore.Hosting/WebHostBuilder.cs b/src/Microsoft.AspNetCore.Hosting/WebHostBuilder.cs
index bcfd4284..25be4976 100644
--- a/src/Microsoft.AspNetCore.Hosting/WebHostBuilder.cs
+++ b/src/Microsoft.AspNetCore.Hosting/WebHostBuilder.cs
@@ -32,7 +32,8 @@ public class WebHostBuilder : IWebHostBuilder
         private WebHostOptions _options;
         private bool _webHostBuilt;
         private Func<WebHostBuilderContext, ILoggerFactory> _createLoggerFactoryDelegate;
-        private List<Action<WebHostBuilderContext, IConfigurationBuilder>> _configureConfigurationBuilderDelegates;
+        private List<Action<WebHostBuilderContext, IConfigurationBuilder>> _configureAppConfigurationBuilderDelegates;
+
         public WebHostBuilderContext Context { get; }
 
         /// <summary>
@@ -43,7 +44,7 @@ public WebHostBuilder()
             _hostingEnvironment = new HostingEnvironment();
             _configureServicesDelegates = new List<Action<WebHostBuilderContext, IServiceCollection>>();
             _configureLoggingDelegates = new List<Action<WebHostBuilderContext, ILoggerFactory>>();
-            _configureConfigurationBuilderDelegates = new List<Action<WebHostBuilderContext, IConfigurationBuilder>>();
+            _configureAppConfigurationBuilderDelegates = new List<Action<WebHostBuilderContext, IConfigurationBuilder>>();
 
             _config = new ConfigurationBuilder()
                 .AddEnvironmentVariables(prefix: "ASPNETCORE_")
@@ -111,6 +112,9 @@ public IWebHostBuilder UseLoggerFactory(ILoggerFactory loggerFactory)
         /// </summary>
         /// <param name="createLoggerFactory">The delegate that constructs an <see cref="IConfigurationBuilder" /></param>
         /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
+        /// <remarks>
+        /// The <see cref="ILoggerFactory"/> on the <see cref="WebHostBuilderContext"/> is uninitialized at this stage.
+        /// </remarks>
         public IWebHostBuilder UseLoggerFactory(Func<WebHostBuilderContext, ILoggerFactory> createLoggerFactory)
         {
             if (createLoggerFactory == null)
@@ -175,7 +179,14 @@ public IWebHostBuilder ConfigureLogging(Action<ILoggerFactory> configureLogging)
         /// Adds a delegate for configuring the provided <see cref="ILoggerFactory"/>. This may be called multiple times.
         /// </summary>
         /// <param name="configureLogging">The delegate that configures the <see cref="ILoggerFactory"/>.</param>
+        /// <typeparam name="T">
+        /// The type of <see cref="ILoggerFactory"/> to configure.
+        /// The delegate will not execute if the type provided does not match the <see cref="ILoggerFactory"/> used by the <see cref="IWebHostBuilder"/>
+        /// </typeparam>
         /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
+        /// <remarks>
+        /// The <see cref="ILoggerFactory"/> on the <see cref="WebHostBuilderContext"/> is uninitialized at this stage.
+        /// </remarks>
         public IWebHostBuilder ConfigureLogging<T>(Action<WebHostBuilderContext, T> configureLogging) where T : ILoggerFactory
         {
             if (configureLogging == null)
@@ -198,6 +209,10 @@ public IWebHostBuilder ConfigureLogging<T>(Action<WebHostBuilderContext, T> conf
         /// </summary>
         /// <param name="configureDelegate">The delegate for configuring the <see cref="IConfigurationBuilder" /> that will be used to construct an <see cref="IConfiguration" />.</param>
         /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
+        /// <remarks>
+        /// The <see cref="IConfiguration"/> and <see cref="ILoggerFactory"/> on the <see cref="WebHostBuilderContext"/> are uninitialized at this stage.
+        /// The <see cref="IConfigurationBuilder"/> is pre-populated with the settings of the <see cref="IWebHostBuilder"/>.
+        /// </remarks>
         public IWebHostBuilder ConfigureAppConfiguration(Action<WebHostBuilderContext, IConfigurationBuilder> configureDelegate)
         {
             if (configureDelegate == null)
@@ -205,7 +220,7 @@ public IWebHostBuilder ConfigureAppConfiguration(Action<WebHostBuilderContext, I
                 throw new ArgumentNullException(nameof(configureDelegate));
             }
 
-            _configureConfigurationBuilderDelegates.Add(configureDelegate);
+            _configureAppConfigurationBuilderDelegates.Add(configureDelegate);
             return this;
         }
 
@@ -270,14 +285,15 @@ private IServiceCollection BuildCommonServices(out AggregateException hostingSta
 
             var services = new ServiceCollection();
             services.AddSingleton(_hostingEnvironment);
+            services.AddSingleton(Context);
 
             var builder = new ConfigurationBuilder()
                 .SetBasePath(_hostingEnvironment.ContentRootPath)
                 .AddInMemoryCollection(_config.AsEnumerable());
 
-            foreach (var configureConfiguration in _configureConfigurationBuilderDelegates)
+            foreach (var configureAppConfiguration in _configureAppConfigurationBuilderDelegates)
             {
-                configureConfiguration(Context, builder);
+                configureAppConfiguration(Context, builder);
             }
 
             var configuration = builder.Build();
@@ -322,7 +338,6 @@ private IServiceCollection BuildCommonServices(out AggregateException hostingSta
                 }
             }
 
-            // Kept for back-compat, will remove once ConfigureLogging is removed.
             foreach (var configureLogging in _configureLoggingDelegates)
             {
                 configureLogging(Context, loggerFactory);
diff --git a/src/Microsoft.AspNetCore.Hosting/WebHostBuilderExtensions.cs b/src/Microsoft.AspNetCore.Hosting/WebHostBuilderExtensions.cs
index 79dcf509..fecc5cc1 100644
--- a/src/Microsoft.AspNetCore.Hosting/WebHostBuilderExtensions.cs
+++ b/src/Microsoft.AspNetCore.Hosting/WebHostBuilderExtensions.cs
@@ -104,7 +104,7 @@ public static IWebHostBuilder UseDefaultServiceProvider(this IWebHostBuilder hos
         /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
         public static IWebHostBuilder ConfigureLogging(this IWebHostBuilder hostBuilder, Action<WebHostBuilderContext, LoggerFactory> configureLogging)
         {
-            return hostBuilder.ConfigureLogging<LoggerFactory>(configureLogging);
+            return hostBuilder.ConfigureLogging(configureLogging);
         }
 
         /// <summary>
diff --git a/test/Microsoft.AspNetCore.Hosting.Tests/WebHostBuilderTests.cs b/test/Microsoft.AspNetCore.Hosting.Tests/WebHostBuilderTests.cs
index 4889ed7c..5cc6c1e7 100644
--- a/test/Microsoft.AspNetCore.Hosting.Tests/WebHostBuilderTests.cs
+++ b/test/Microsoft.AspNetCore.Hosting.Tests/WebHostBuilderTests.cs
@@ -35,10 +35,11 @@ public void Build_honors_UseStartup_with_string()
         {
             var builder = CreateWebHostBuilder().UseServer(new TestServer());
 
-            var host = (WebHost)builder.UseStartup("MyStartupAssembly").Build();
-
-            Assert.Equal("MyStartupAssembly", host.Options.ApplicationName);
-            Assert.Equal("MyStartupAssembly", host.Options.StartupAssembly);
+            using (var host = (WebHost)builder.UseStartup("MyStartupAssembly").Build())
+            {
+                Assert.Equal("MyStartupAssembly", host.Options.ApplicationName);
+                Assert.Equal("MyStartupAssembly", host.Options.StartupAssembly);
+            }
         }
 
         [Fact]
@@ -46,8 +47,7 @@ public async Task StartupMissing_Fallback()
         {
             var builder = CreateWebHostBuilder();
             var server = new TestServer();
-            var host = builder.UseServer(server).UseStartup("MissingStartupAssembly").Build();
-            using (host)
+            using (var host = builder.UseServer(server).UseStartup("MissingStartupAssembly").Build())
             {
                 await host.StartAsync();
                 await AssertResponseContains(server.RequestDelegate, "MissingStartupAssembly");
@@ -158,9 +158,10 @@ public void DefaultCreatesLoggerFactory()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
 
-            var host = (WebHost)hostBuilder.Build();
-
-            Assert.NotNull(host.Services.GetService<ILoggerFactory>());
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                Assert.NotNull(host.Services.GetService<ILoggerFactory>());
+            }
         }
 
         [Fact]
@@ -195,9 +196,10 @@ public void UseLoggerFactoryHonored()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
 
-            var host = (WebHost)hostBuilder.Build();
-
-            Assert.Same(loggerFactory, host.Services.GetService<ILoggerFactory>());
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                Assert.Same(loggerFactory, host.Services.GetService<ILoggerFactory>());
+            }
         }
 
         [Fact]
@@ -216,8 +218,10 @@ public void MultipleConfigureLoggingInvokedInOrder()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
 
-            var host = (WebHost)hostBuilder.Build();
-            Assert.Equal(2, callCount);
+            using (hostBuilder.Build())
+            {
+                Assert.Equal(2, callCount);
+            }
         }
 
         [Fact]
@@ -230,9 +234,10 @@ public void UseLoggerFactoryDelegateIsHonored()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
 
-            var host = (WebHost)hostBuilder.Build();
-
-            Assert.Same(loggerFactory, host.Services.GetService<ILoggerFactory>());
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                Assert.Same(loggerFactory, host.Services.GetService<ILoggerFactory>());
+            }
         }
 
         [Fact]
@@ -252,21 +257,23 @@ public void UseLoggerFactoryFuncAndConfigureLoggingCompose()
                 })
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
-            var host = (WebHost)hostBuilder.Build();
-            Assert.Equal(2, callCount);
-            Assert.Same(loggerFactory, host.Services.GetService<ILoggerFactory>());
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                Assert.Equal(2, callCount);
+                Assert.Same(loggerFactory, host.Services.GetService<ILoggerFactory>());
+            }
         }
 
         [Fact]
-        public void HostingContextCanBeUsed()
+        public void HostingContextContainsAppConfigurationDuringConfigureLogging()
         {
             var hostBuilder = new WebHostBuilder()
-                 .ConfigureAppConfiguration((context, configBuilder) => configBuilder
-                    .AddInMemoryCollection(
-                            new KeyValuePair<string, string>[]
-                            {
-                                new KeyValuePair<string, string>("key1", "value1")
-                            }))
+                 .ConfigureAppConfiguration((context, configBuilder) =>
+                    configBuilder.AddInMemoryCollection(
+                        new KeyValuePair<string, string>[]
+                        {
+                            new KeyValuePair<string, string>("key1", "value1")
+                        }))
                  .ConfigureLogging((context, factory) =>
                  {
                      Assert.Equal("value1", context.Configuration["key1"]);
@@ -274,10 +281,27 @@ public void HostingContextCanBeUsed()
                  .UseServer(new TestServer())
                  .UseStartup<StartupNoServices>();
 
-            hostBuilder.Build();
+            using (hostBuilder.Build()) { }
+        }
+
+        [Fact]
+        public void HostingContextContainsAppConfigurationDuringConfigureServices()
+        {
+            var hostBuilder = new WebHostBuilder()
+                 .ConfigureAppConfiguration((context, configBuilder) =>
+                    configBuilder.AddInMemoryCollection(
+                        new KeyValuePair<string, string>[]
+                        {
+                            new KeyValuePair<string, string>("key1", "value1")
+                        }))
+                 .ConfigureServices((context, factory) =>
+                 {
+                     Assert.Equal("value1", context.Configuration["key1"]);
+                 })
+                 .UseServer(new TestServer())
+                 .UseStartup<StartupNoServices>();
 
-            //Verify property on builder is set.
-            Assert.Equal("value1", hostBuilder.Context.Configuration["key1"]);
+            using (hostBuilder.Build()) { }
         }
 
         [Fact]
@@ -293,8 +317,10 @@ public void ConfigureLoggingCalledIfLoggerFactoryTypeMatches()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
 
-            var host = (WebHost)hostBuilder.Build();
-            Assert.Equal(1, callCount);
+            using (hostBuilder.Build())
+            {
+                Assert.Equal(1, callCount);
+            }
         }
 
         [Fact]
@@ -310,8 +336,10 @@ public void ConfigureLoggingNotCalledIfLoggerFactoryTypeDoesNotMatches()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
 
-            var host = (WebHost)hostBuilder.Build();
-            Assert.Equal(0, callCount);
+            using (hostBuilder.Build())
+            {
+                Assert.Equal(0, callCount);
+            }
         }
 
         [Fact]
@@ -325,8 +353,11 @@ public void CanUseCustomLoggerFactory()
                 })
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
-            var host = (WebHost)hostBuilder.Build();
-            Assert.IsType(typeof(CustomLoggerFactory), host.Services.GetService<ILoggerFactory>());
+
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                Assert.IsType(typeof(CustomLoggerFactory), host.Services.GetService<ILoggerFactory>());
+            }
         }
 
         [Fact]
@@ -335,9 +366,11 @@ public void ThereIsAlwaysConfiguration()
             var hostBuilder = new WebHostBuilder()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
-            var host = (WebHost)hostBuilder.Build();
 
-            Assert.NotNull(host.Services.GetService<IConfiguration>());
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                Assert.NotNull(host.Services.GetService<IConfiguration>());
+            }
         }
 
         [Fact]
@@ -352,7 +385,8 @@ public void ConfigureConfigurationSettingsPropagated()
                 })
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
-            var host = (WebHost)hostBuilder.Build();
+
+            using (hostBuilder.Build()) { }
         }
 
         [Fact]
@@ -371,11 +405,13 @@ public void CanConfigureConfigurationAndRetrieveFromDI()
                 })
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
-            var host = (WebHost)hostBuilder.Build();
 
-            var config = host.Services.GetService<IConfiguration>();
-            Assert.NotNull(config);
-            Assert.Equal("value1", config["key1"]);
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                var config = host.Services.GetService<IConfiguration>();
+                Assert.NotNull(config);
+                Assert.Equal("value1", config["key1"]);
+            }
         }
 
         [Fact]
@@ -419,11 +455,13 @@ public void ConfigureServices_CanBeCalledMultipleTimes()
                 })
                 .Configure(app => { });
 
-            var host = hostBuilder.Build();
-            Assert.Equal(2, callCount);
+            using (var host = hostBuilder.Build())
+            {
+                Assert.Equal(2, callCount);
 
-            Assert.NotNull(host.Services.GetRequiredService<ServiceA>());
-            Assert.NotNull(host.Services.GetRequiredService<ServiceB>());
+                Assert.NotNull(host.Services.GetRequiredService<ServiceA>());
+                Assert.NotNull(host.Services.GetRequiredService<ServiceB>());
+            }
         }
 
         [Fact]
@@ -435,9 +473,10 @@ public void CodeBasedSettingsCodeBasedOverride()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
 
-            var host = (WebHost)hostBuilder.Build();
-
-            Assert.Equal("EnvB", host.Options.Environment);
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                Assert.Equal("EnvB", host.Options.Environment);
+            }
         }
 
         [Fact]
@@ -458,9 +497,10 @@ public void CodeBasedSettingsConfigBasedOverride()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
 
-            var host = (WebHost)hostBuilder.Build();
-
-            Assert.Equal("EnvB", host.Options.Environment);
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                Assert.Equal("EnvB", host.Options.Environment);
+            }
         }
 
         [Fact]
@@ -481,9 +521,10 @@ public void ConfigBasedSettingsCodeBasedOverride()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
 
-            var host = (WebHost)hostBuilder.Build();
-
-            Assert.Equal("EnvB", host.Options.Environment);
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                Assert.Equal("EnvB", host.Options.Environment);
+            }
         }
 
         [Fact]
@@ -513,9 +554,10 @@ public void ConfigBasedSettingsConfigBasedOverride()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>();
 
-            var host = (WebHost)hostBuilder.Build();
-
-            Assert.Equal("EnvB", host.Options.Environment);
+            using (var host = (WebHost)hostBuilder.Build())
+            {
+                Assert.Equal("EnvB", host.Options.Environment);
+            }
         }
 
         [Fact]
@@ -530,14 +572,17 @@ public void UseEnvironmentIsNotOverriden()
             var config = builder.Build();
 
             var expected = "MY_TEST_ENVIRONMENT";
-            var host = new WebHostBuilder()
+
+
+            using (var host = new WebHostBuilder()
                 .UseConfiguration(config)
                 .UseEnvironment(expected)
                 .UseServer(new TestServer())
                 .UseStartup("Microsoft.AspNetCore.Hosting.Tests")
-                .Build();
-
-            Assert.Equal(expected, host.Services.GetService<IHostingEnvironment>().EnvironmentName);
+                .Build())
+            {
+                Assert.Equal(expected, host.Services.GetService<IHostingEnvironment>().EnvironmentName);
+            }
         }
 
         [Fact]
@@ -552,14 +597,12 @@ public void BuildAndDispose()
             var config = builder.Build();
 
             var expected = "MY_TEST_ENVIRONMENT";
-            var host = new WebHostBuilder()
+            using (var host = new WebHostBuilder()
                 .UseConfiguration(config)
                 .UseEnvironment(expected)
                 .UseServer(new TestServer())
                 .UseStartup("Microsoft.AspNetCore.Hosting.Tests")
-                .Build();
-
-            host.Dispose();
+                .Build()) { }
         }
 
         [Fact]
@@ -573,105 +616,113 @@ public void UseBasePathConfiguresBasePath()
                 .AddInMemoryCollection(vals);
             var config = builder.Build();
 
-            var host = new WebHostBuilder()
+            using (var host = new WebHostBuilder()
                 .UseConfiguration(config)
                 .UseContentRoot("/")
                 .UseServer(new TestServer())
                 .UseStartup("Microsoft.AspNetCore.Hosting.Tests")
-                .Build();
-
-            Assert.Equal("/", host.Services.GetService<IHostingEnvironment>().ContentRootPath);
+                .Build())
+            {
+                Assert.Equal("/", host.Services.GetService<IHostingEnvironment>().ContentRootPath);
+            }
         }
 
         [Fact]
         public void RelativeContentRootIsResolved()
         {
-            var host = new WebHostBuilder()
+            using (var host = new WebHostBuilder()
                 .UseContentRoot("testroot")
                 .UseServer(new TestServer())
                 .UseStartup("Microsoft.AspNetCore.Hosting.Tests")
-                .Build();
-
-            var basePath = host.Services.GetRequiredService<IHostingEnvironment>().ContentRootPath;
-            Assert.True(Path.IsPathRooted(basePath));
-            Assert.EndsWith(Path.DirectorySeparatorChar + "testroot", basePath);
+                .Build())
+            {
+                var basePath = host.Services.GetRequiredService<IHostingEnvironment>().ContentRootPath;
+                Assert.True(Path.IsPathRooted(basePath));
+                Assert.EndsWith(Path.DirectorySeparatorChar + "testroot", basePath);
+            }
         }
 
         [Fact]
         public void DefaultContentRootIsApplicationBasePath()
         {
-            var host = new WebHostBuilder()
+            using (var host = new WebHostBuilder()
                 .UseServer(new TestServer())
                 .UseStartup("Microsoft.AspNetCore.Hosting.Tests")
-                .Build();
-
-            var appBase = PlatformServices.Default.Application.ApplicationBasePath;
-            Assert.Equal(appBase, host.Services.GetService<IHostingEnvironment>().ContentRootPath);
+                .Build())
+            {
+                var appBase = PlatformServices.Default.Application.ApplicationBasePath;
+                Assert.Equal(appBase, host.Services.GetService<IHostingEnvironment>().ContentRootPath);
+            }
         }
 
         [Fact]
         public void DefaultApplicationNameToStartupAssemblyName()
         {
             var builder = new ConfigurationBuilder();
-            var host = new WebHostBuilder()
+            using (var host = new WebHostBuilder()
                 .UseServer(new TestServer())
                 .UseStartup("Microsoft.AspNetCore.Hosting.Tests")
-                .Build();
-
-            var hostingEnv = host.Services.GetService<IHostingEnvironment>();
-            Assert.Equal("Microsoft.AspNetCore.Hosting.Tests", hostingEnv.ApplicationName);
+                .Build())
+            {
+                var hostingEnv = host.Services.GetService<IHostingEnvironment>();
+                Assert.Equal("Microsoft.AspNetCore.Hosting.Tests", hostingEnv.ApplicationName);
+            }
         }
 
         [Fact]
         public void DefaultApplicationNameToStartupType()
         {
             var builder = new ConfigurationBuilder();
-            var host = new WebHostBuilder()
+            using (var host = new WebHostBuilder()
                 .UseServer(new TestServer())
                 .UseStartup<StartupNoServices>()
                 .UseStartup("Microsoft.AspNetCore.Hosting.Tests.NonExistent")
-                .Build();
-
-            var hostingEnv = host.Services.GetService<IHostingEnvironment>();
-            Assert.Equal("Microsoft.AspNetCore.Hosting.Tests.NonExistent", hostingEnv.ApplicationName);
+                .Build())
+            {
+                var hostingEnv = host.Services.GetService<IHostingEnvironment>();
+                Assert.Equal("Microsoft.AspNetCore.Hosting.Tests.NonExistent", hostingEnv.ApplicationName);
+            }
         }
 
         [Fact]
         public void DefaultApplicationNameAndBasePathToStartupMethods()
         {
             var builder = new ConfigurationBuilder();
-            var host = new WebHostBuilder()
+            using (var host = new WebHostBuilder()
                 .UseServer(new TestServer())
                 .Configure(app => { })
                 .UseStartup("Microsoft.AspNetCore.Hosting.Tests.NonExistent")
-                .Build();
-
-            var hostingEnv = host.Services.GetService<IHostingEnvironment>();
-            Assert.Equal("Microsoft.AspNetCore.Hosting.Tests.NonExistent", hostingEnv.ApplicationName);
+                .Build())
+            {
+                var hostingEnv = host.Services.GetService<IHostingEnvironment>();
+                Assert.Equal("Microsoft.AspNetCore.Hosting.Tests.NonExistent", hostingEnv.ApplicationName);
+            }
         }
 
         [Fact]
         public void Configure_SupportsNonStaticMethodDelegate()
         {
-            var host = new WebHostBuilder()
+            using (var host = new WebHostBuilder()
                 .UseServer(new TestServer())
                 .Configure(app => { })
-                .Build();
-
-            var hostingEnv = host.Services.GetService<IHostingEnvironment>();
-            Assert.Equal("Microsoft.AspNetCore.Hosting.Tests", hostingEnv.ApplicationName);
+                .Build())
+            {
+                var hostingEnv = host.Services.GetService<IHostingEnvironment>();
+                Assert.Equal("Microsoft.AspNetCore.Hosting.Tests", hostingEnv.ApplicationName);
+            }
         }
 
         [Fact]
         public void Configure_SupportsStaticMethodDelegate()
         {
-            var host = new WebHostBuilder()
+            using (var host = new WebHostBuilder()
                 .UseServer(new TestServer())
                 .Configure(StaticConfigureMethod)
-                .Build();
-
-            var hostingEnv = host.Services.GetService<IHostingEnvironment>();
-            Assert.Equal("Microsoft.AspNetCore.Hosting.Tests", hostingEnv.ApplicationName);
+                .Build())
+            {
+                var hostingEnv = host.Services.GetService<IHostingEnvironment>();
+                Assert.Equal("Microsoft.AspNetCore.Hosting.Tests", hostingEnv.ApplicationName);
+            }
         }
 
         [Fact]
@@ -679,13 +730,13 @@ public void Build_DoesNotAllowBuildingMuiltipleTimes()
         {
             var builder = CreateWebHostBuilder();
             var server = new TestServer();
-            builder.UseServer(server)
+            using (builder.UseServer(server)
                 .UseStartup<StartupNoServices>()
-                .Build();
-
-            var ex = Assert.Throws<InvalidOperationException>(() => builder.Build());
-
-            Assert.Equal("WebHostBuilder allows creation only of a single instance of WebHost", ex.Message);
+                .Build())
+            {
+                var ex = Assert.Throws<InvalidOperationException>(() => builder.Build());
+                Assert.Equal("WebHostBuilder allows creation only of a single instance of WebHost", ex.Message);
+            }
         }
 
         [Fact]
@@ -693,13 +744,13 @@ public void Build_PassesSameAutoCreatedILoggerFactoryEverywhere()
         {
             var builder = CreateWebHostBuilder();
             var server = new TestServer();
-            var host = builder.UseServer(server)
+            using (var host = builder.UseServer(server)
                 .UseStartup<StartupWithILoggerFactory>()
-                .Build();
-
-            var startup = host.Services.GetService<StartupWithILoggerFactory>();
-
-            Assert.Equal(startup.ConfigureLoggerFactory, startup.ConstructorLoggerFactory);
+                .Build())
+            {
+                var startup = host.Services.GetService<StartupWithILoggerFactory>();
+                Assert.Equal(startup.ConfigureLoggerFactory, startup.ConstructorLoggerFactory);
+            }
         }
 
         [Fact]
@@ -708,15 +759,15 @@ public void Build_PassesSamePassedILoggerFactoryEverywhere()
             var factory = new LoggerFactory();
             var builder = CreateWebHostBuilder();
             var server = new TestServer();
-            var host = builder.UseServer(server)
+            using (var host = builder.UseServer(server)
                 .UseLoggerFactory(factory)
                 .UseStartup<StartupWithILoggerFactory>()
-                .Build();
-
-            var startup = host.Services.GetService<StartupWithILoggerFactory>();
-
-            Assert.Equal(factory, startup.ConfigureLoggerFactory);
-            Assert.Equal(factory, startup.ConstructorLoggerFactory);
+                .Build())
+            {
+                var startup = host.Services.GetService<StartupWithILoggerFactory>();
+                Assert.Equal(factory, startup.ConfigureLoggerFactory);
+                Assert.Equal(factory, startup.ConstructorLoggerFactory);
+            }
         }
 
         [Fact]
@@ -726,12 +777,10 @@ public void Build_PassedILoggerFactoryNotDisposed()
             var builder = CreateWebHostBuilder();
             var server = new TestServer();
 
-            var host = builder.UseServer(server)
+            using (var host = builder.UseServer(server)
                 .UseLoggerFactory(factory)
                 .UseStartup<StartupWithILoggerFactory>()
-                .Build();
-
-            host.Dispose();
+                .Build()) { }
 
             Assert.Equal(false, factory.Disposed);
         }
@@ -743,13 +792,14 @@ public void Build_DoesNotOverrideILoggerFactorySetByConfigureServices()
             var builder = CreateWebHostBuilder();
             var server = new TestServer();
 
-            var host = builder.UseServer(server)
+            using (var host = builder.UseServer(server)
                 .ConfigureServices(collection => collection.AddSingleton<ILoggerFactory>(factory))
                 .UseStartup<StartupWithILoggerFactory>()
-                .Build();
-
-            var factoryFromHost = host.Services.GetService<ILoggerFactory>();
-            Assert.Equal(factory, factoryFromHost);
+                .Build())
+            {
+                var factoryFromHost = host.Services.GetService<ILoggerFactory>();
+                Assert.Equal(factory, factoryFromHost);
+            }
         }
 
         [Fact]
@@ -761,9 +811,10 @@ public void Build_RunsHostingStartupAssembliesIfSpecified()
                 .Configure(app => { })
                 .UseServer(new TestServer());
 
-            var host = (WebHost)builder.Build();
-
-            Assert.Equal("1", builder.GetSetting("testhostingstartup"));
+            using (var host = builder.Build())
+            {
+                Assert.Equal("1", builder.GetSetting("testhostingstartup"));
+            }
         }
 
         [Fact]
@@ -782,10 +833,11 @@ public void Build_RunsHostingStartupAssembliesBeforeApplication()
                 })
                 .UseServer(new TestServer());
 
-            var host = (WebHost)builder.Build();
-
-            Assert.NotNull(startup.ServiceADescriptor);
-            Assert.NotNull(startup.ServiceA);
+            using (builder.Build())
+            {
+                Assert.NotNull(startup.ServiceADescriptor);
+                Assert.NotNull(startup.ServiceA);
+            }
         }
 
         [Fact]
@@ -802,9 +854,11 @@ public void Build_ConfigureLoggingInHostingStartupWorks()
                 })
                 .UseServer(new TestServer());
 
-            var host = (WebHost)builder.Build();
-            var sink = host.Services.GetRequiredService<ITestSink>();
-            Assert.True(sink.Writes.Any(w => w.State.ToString() == "From startup"));
+            using (var host = (WebHost)builder.Build())
+            {
+                var sink = host.Services.GetRequiredService<ITestSink>();
+                Assert.True(sink.Writes.Any(w => w.State.ToString() == "From startup"));
+            }
         }
 
         [Fact]
@@ -814,9 +868,10 @@ public void Build_DoesNotRunHostingStartupAssembliesDoNotRunIfNotSpecified()
                 .Configure(app => { })
                 .UseServer(new TestServer());
 
-            var host = (WebHost)builder.Build();
-
-            Assert.Null(builder.GetSetting("testhostingstartup"));
+            using (builder.Build())
+            {
+                Assert.Null(builder.GetSetting("testhostingstartup"));
+            }
         }
 
         [Fact]
@@ -828,7 +883,7 @@ public void Build_ThrowsIfUnloadableAssemblyNameInHostingStartupAssemblies()
                 .Configure(app => { })
                 .UseServer(new TestServer());
 
-            var ex = Assert.Throws<AggregateException>(() => (WebHost)builder.Build());
+            var ex = Assert.Throws<AggregateException>(() => builder.Build());
             Assert.IsType<InvalidOperationException>(ex.InnerExceptions[0]);
             Assert.IsType<FileNotFoundException>(ex.InnerExceptions[0].InnerException);
         }
@@ -867,8 +922,7 @@ public void HostingStartupTypeCtorThrowsIfNotIHosting()
             Assert.Throws<ArgumentException>(() => new HostingStartupAttribute(typeof(WebHostTests)));
         }
 
-        private static void StaticConfigureMethod(IApplicationBuilder app)
-        { }
+        private static void StaticConfigureMethod(IApplicationBuilder app) { }
 
         private IWebHostBuilder CreateWebHostBuilder()
         {
@@ -898,10 +952,7 @@ private class TestServer : IServer
             IFeatureCollection IServer.Features { get; }
             public RequestDelegate RequestDelegate { get; private set; }
 
-            public void Dispose()
-            {
-
-            }
+            public void Dispose() { }
 
             public Task StartAsync<TContext>(IHttpApplication<TContext> application, CancellationToken cancellationToken)
             {
@@ -923,10 +974,7 @@ public Task StartAsync<TContext>(IHttpApplication<TContext> application, Cancell
                 return Task.CompletedTask;
             }
 
-            public Task StopAsync(CancellationToken cancellationToken)
-            {
-                return Task.CompletedTask;
-            }
+            public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
         }
 
         internal class StartupVerifyServiceA : IStartup
@@ -964,39 +1012,21 @@ public class TestLoggerProvider : ILoggerProvider
         {
             public TestSink Sink { get; set; } = new TestSink();
 
-            public ILogger CreateLogger(string categoryName)
-            {
-                return new TestLogger(categoryName, Sink, enabled: true);
-            }
+            public ILogger CreateLogger(string categoryName) => new TestLogger(categoryName, Sink, enabled: true);
 
-            public void Dispose()
-            {
-
-            }
+            public void Dispose() { }
         }
 
         private class ServiceC
         {
-            public ServiceC(ServiceD serviceD)
-            {
-
-            }
+            public ServiceC(ServiceD serviceD) { }
         }
 
-        internal class ServiceD
-        {
+        internal class ServiceD { }
 
-        }
+        internal class ServiceA { }
 
-        internal class ServiceA
-        {
-
-        }
-
-        internal class ServiceB
-        {
-
-        }
+        internal class ServiceB { }
 
         private class DisposableLoggerFactory : ILoggerFactory
         {
@@ -1007,14 +1037,9 @@ public void Dispose()
 
             public bool Disposed { get; set; }
 
-            public ILogger CreateLogger(string categoryName)
-            {
-                return NullLogger.Instance;
-            }
+            public ILogger CreateLogger(string categoryName) => NullLogger.Instance;
 
-            public void AddProvider(ILoggerProvider provider)
-            {
-            }
+            public void AddProvider(ILoggerProvider provider) { }
         }
     }
 }