Add extension methods in our test host package to streamline setup of apps.

* Create a sources package to encode the convention followed in our templates to create a WebHost.
* Add an extension method to setup the content root relative to the solution folder.
* Add a factory method to create a WebHostBuilder based on the pattern followed in our template.

Hosting.sln

@@ -1,6 +1,6 @@
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
-VisualStudioVersion = 15.0.26730.10
+VisualStudioVersion = 15.0.26913.0
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{E0497F39-AFFB-4819-A116-E39E361915AB}"
 	ProjectSection(SolutionItems) = preProject
@@ -63,6 +63,10 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "GenericWebHost", "samples\G
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.Extensions.Hosting.Tests", "test\Microsoft.Extensions.Hosting.Tests\Microsoft.Extensions.Hosting.Tests.csproj", "{45E296BB-7628-49AF-B5A5-04CD9A89CAD3}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Tests", "test\Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Tests\Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Tests.csproj", "{3834E274-3AF5-4751-8857-5B67BBE607DD}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "BuildWebHostPatternTestSite", "test\TestAssets\BuildWebHostPatternTestSite\BuildWebHostPatternTestSite.csproj", "{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -293,6 +297,30 @@ Global
 		{45E296BB-7628-49AF-B5A5-04CD9A89CAD3}.Release|Mixed Platforms.Build.0 = Release|Any CPU
 		{45E296BB-7628-49AF-B5A5-04CD9A89CAD3}.Release|x86.ActiveCfg = Release|Any CPU
 		{45E296BB-7628-49AF-B5A5-04CD9A89CAD3}.Release|x86.Build.0 = Release|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Debug|x86.Build.0 = Debug|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Release|Any CPU.Build.0 = Release|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Release|x86.ActiveCfg = Release|Any CPU
+		{3834E274-3AF5-4751-8857-5B67BBE607DD}.Release|x86.Build.0 = Release|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Debug|x86.Build.0 = Debug|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Release|Any CPU.Build.0 = Release|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Release|x86.ActiveCfg = Release|Any CPU
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -312,12 +340,14 @@ Global
 		{AB0B7394-278D-4838-A59C-276ED88D00CC} = {FEB39027-9158-4DE2-997F-7ADAEF8188D0}
 		{FA7D2012-C1B4-4AF7-9ADD-381B2004EA16} = {FEB39027-9158-4DE2-997F-7ADAEF8188D0}
 		{EDFF02F0-A8A4-4EB1-A179-94D7500FB266} = {FA7D2012-C1B4-4AF7-9ADD-381B2004EA16}
-		{58194285-5891-464A-A96B-0FE043029E8A} = {FA7D2012-C1B4-4AF7-9ADD-381B2004EA16}
+		{58194285-5891-464A-A96B-0FE043029E8A} = {FEB39027-9158-4DE2-997F-7ADAEF8188D0}
 		{F894D8C5-B760-4734-AD31-3CA6FC557CCF} = {FA7D2012-C1B4-4AF7-9ADD-381B2004EA16}
 		{8529E5F7-059F-4A06-AD6E-ECDF4F4838FE} = {9C7520A0-F2EB-411C-8BB2-80B39C937217}
 		{1DA77D55-5DB9-4426-87DC-758579335944} = {E0497F39-AFFB-4819-A116-E39E361915AB}
 		{FCDD1C82-623C-4779-8A9C-B0D827CEA8BF} = {9C7520A0-F2EB-411C-8BB2-80B39C937217}
 		{45E296BB-7628-49AF-B5A5-04CD9A89CAD3} = {FEB39027-9158-4DE2-997F-7ADAEF8188D0}
+		{3834E274-3AF5-4751-8857-5B67BBE607DD} = {FEB39027-9158-4DE2-997F-7ADAEF8188D0}
+		{37C4BD55-CD39-4C4E-BA01-0AEAFCE128F1} = {FA7D2012-C1B4-4AF7-9ADD-381B2004EA16}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {AABD536D-E05F-409B-A716-535E0C478076}

NuGetPackageVerifier.json

@@ -5,6 +5,7 @@
     ],
     "packages": {
       "Microsoft.AspNetCore.Certificates.Configuration.Sources": {},
+      "Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Sources": {},
       "Microsoft.AspNetCore.Server.IntegrationTesting": {}
     }
   },

shared/Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Sources/FactoryResolutionResult.cs

@@ -0,0 +1,50 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNetCore.Hosting.WebHostBuilderFactory
+{
+    internal class FactoryResolutionResult
+    {
+        public FactoryResolutionResultKind ResultKind { get; set; }
+        public Type ProgramType { get; set; }
+        public Func<string[], IWebHost> WebHostFactory { get; set; }
+        public Func<string[], IWebHostBuilder> WebHostBuilderFactory { get; set; }
+
+        internal static FactoryResolutionResult NoBuildWebHost(Type programType) =>
+            new FactoryResolutionResult
+            {
+                ProgramType = programType,
+                ResultKind = FactoryResolutionResultKind.NoBuildWebHost
+            };
+
+        internal static FactoryResolutionResult NoCreateWebHostBuilder(Type programType) =>
+            new FactoryResolutionResult
+            {
+                ProgramType = programType,
+                ResultKind = FactoryResolutionResultKind.NoCreateWebHostBuilder
+            };
+
+        internal static FactoryResolutionResult NoEntryPoint() =>
+            new FactoryResolutionResult
+            {
+                ResultKind = FactoryResolutionResultKind.NoEntryPoint
+            };
+
+        internal static FactoryResolutionResult Succeded(Func<string[], IWebHost> factory, Type programType) => new FactoryResolutionResult
+        {
+            ProgramType = programType,
+            ResultKind = FactoryResolutionResultKind.Success,
+            WebHostFactory = factory
+        };
+
+        internal static FactoryResolutionResult Succeded(Func<string[], IWebHostBuilder> factory, Type programType) => new FactoryResolutionResult
+        {
+            ProgramType = programType,
+            ResultKind = FactoryResolutionResultKind.Success,
+            WebHostBuilderFactory = factory,
+            WebHostFactory = args => factory(args).Build()
+        };
+    }
+}

shared/Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Sources/FactoryResolutionResultKind.cs

@@ -0,0 +1,14 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+
+namespace Microsoft.AspNetCore.Hosting.WebHostBuilderFactory
+{
+    internal enum FactoryResolutionResultKind
+    {
+        Success,
+        NoEntryPoint,
+        NoCreateWebHostBuilder,
+        NoBuildWebHost
+    }
+}

shared/Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Sources/WebHostFactoryResolver.cs

@@ -0,0 +1,62 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Reflection;
+
+namespace Microsoft.AspNetCore.Hosting.WebHostBuilderFactory
+{
+    internal class WebHostFactoryResolver
+    {
+        public static readonly string CreateWebHostBuilder = nameof(CreateWebHostBuilder);
+        public static readonly string BuildWebHost = nameof(BuildWebHost);
+
+        public static FactoryResolutionResult ResolveWebHostBuilderFactory(Assembly assembly)
+        {
+            var programType = assembly?.EntryPoint?.DeclaringType;
+            if (programType == null)
+            {
+                return FactoryResolutionResult.NoEntryPoint();
+            }
+
+            var factory = programType?.GetTypeInfo().GetDeclaredMethod(CreateWebHostBuilder);
+            if (factory == null)
+            {
+                return FactoryResolutionResult.NoCreateWebHostBuilder(programType);
+            }
+
+            return FactoryResolutionResult.Succeded(args => (IWebHostBuilder)factory.Invoke(null, new object[] { args }), programType);
+        }
+
+        public static FactoryResolutionResult ResolveWebHostFactory(Assembly assembly)
+        {
+            // We want to give priority to BuildWebHost over CreateWebHostBuilder for backwards
+            // compatibility with existing projects that follow the old pattern.
+            var findResult = ResolveWebHostBuilderFactory(assembly);
+            switch (findResult.ResultKind)
+            {
+                case FactoryResolutionResultKind.NoEntryPoint:
+                    return findResult;
+                case FactoryResolutionResultKind.Success:
+                case FactoryResolutionResultKind.NoCreateWebHostBuilder:
+                    var buildWebHostMethod = findResult.ProgramType.GetTypeInfo().GetDeclaredMethod("BuildWebHost");
+                    if (buildWebHostMethod == null)
+                    {
+                        if (findResult.ResultKind == FactoryResolutionResultKind.Success)
+                        {
+                            return findResult;
+                        }
+
+                        return FactoryResolutionResult.NoBuildWebHost(findResult.ProgramType);
+                    }
+                    else
+                    {
+                        return FactoryResolutionResult.Succeded(args => (IWebHost)buildWebHostMethod.Invoke(null, new object[] { args }), findResult.ProgramType);
+                    }
+                case FactoryResolutionResultKind.NoBuildWebHost:
+                default:
+                    throw new InvalidOperationException();
+            }
+        }
+    }
+}

src/Microsoft.AspNetCore.TestHost/Microsoft.AspNetCore.TestHost.csproj

@@ -8,6 +8,12 @@
     <PackageTags>aspnetcore;hosting;testing</PackageTags>
   </PropertyGroup>
 
+  <ItemGroup>
+    <Compile Include="..\..\shared\Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Sources\FactoryResolutionResult.cs" />
+    <Compile Include="..\..\shared\Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Sources\FactoryResolutionResultKind.cs" />
+    <Compile Include="..\..\shared\Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Sources\WebHostFactoryResolver.cs" />
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="..\Microsoft.AspNetCore.Hosting\Microsoft.AspNetCore.Hosting.csproj" />
   </ItemGroup>

src/Microsoft.AspNetCore.TestHost/WebHostBuilderExtensions.cs

@@ -2,6 +2,8 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.IO;
+using System.Linq;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -47,6 +49,35 @@ namespace Microsoft.AspNetCore.TestHost
             return webHostBuilder;
         }
 
+        public static IWebHostBuilder UseSolutionRelativeContentRoot(
+            this IWebHostBuilder builder,
+            string solutionRelativePath,
+            string solutionName = "*.sln")
+        {
+            if (solutionRelativePath == null)
+            {
+                throw new ArgumentNullException(nameof(solutionRelativePath));
+            }
+
+            var applicationBasePath = AppContext.BaseDirectory;
+
+            var directoryInfo = new DirectoryInfo(applicationBasePath);
+            do
+            {
+                var solutionPath = Directory.EnumerateFiles(directoryInfo.FullName, solutionName).FirstOrDefault();
+                if (solutionPath != null)
+                {
+                    builder.UseContentRoot(Path.GetFullPath(Path.Combine(directoryInfo.FullName, solutionRelativePath)));
+                    return builder;
+                }
+
+                directoryInfo = directoryInfo.Parent;
+            }
+            while (directoryInfo.Parent != null);
+
+            throw new InvalidOperationException($"Solution root could not be located using application root {applicationBasePath}.");
+        }
+
         private class ConfigureTestServicesStartupConfigureServicesFilter : IStartupConfigureServicesFilter
         {
             private readonly Action<IServiceCollection> _servicesConfiguration;

src/Microsoft.AspNetCore.TestHost/WebHostBuilderFactory.cs

@@ -0,0 +1,26 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Reflection;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Hosting.WebHostBuilderFactory;
+
+namespace Microsoft.AspNetCore.TestHost
+{
+    public static class WebHostBuilderFactory
+    {
+        public static IWebHostBuilder CreateFromAssemblyEntryPoint(Assembly assembly, string [] args)
+        {
+            var result = WebHostFactoryResolver.ResolveWebHostBuilderFactory(assembly);
+            if (result.ResultKind != FactoryResolutionResultKind.Success)
+            {
+                return null;
+            }
+
+            return result.WebHostBuilderFactory(args);
+        }
+
+        public static IWebHostBuilder CreateFromTypesAssemblyEntryPoint<T>(string[] args) =>
+            CreateFromAssemblyEntryPoint(typeof(T).Assembly, args);
+    }
+}

test/Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Tests/Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Tests.csproj

@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>netcoreapp2.0;net461</TargetFrameworks>
+    <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netcoreapp2.0</TargetFrameworks>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="..\..\shared\Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Sources\**\*.cs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\Microsoft.AspNetCore.Hosting.Abstractions\Microsoft.AspNetCore.Hosting.Abstractions.csproj" />
+    <ProjectReference Include="..\TestAssets\BuildWebHostPatternTestSite\BuildWebHostPatternTestSite.csproj" />
+    <ProjectReference Include="..\TestAssets\IStartupInjectionAssemblyName\IStartupInjectionAssemblyName.csproj" />
+  </ItemGroup>
+
+</Project>

test/Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Tests/WebHostFactoryResolverTests.cs

@@ -0,0 +1,60 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Hosting.WebHostBuilderFactory.Tests
+{
+    public class WebHostFactoryResolverTests
+    {
+        [Fact]
+        public void CanFindWebHostBuilder_CreateWebHostBuilderPattern()
+        {
+            // Arrange & Act
+            var resolverResult = WebHostFactoryResolver.ResolveWebHostBuilderFactory(typeof(IStartupInjectionAssemblyName.Startup).Assembly);
+
+            // Assert
+            Assert.Equal(FactoryResolutionResultKind.Success, resolverResult.ResultKind);
+            Assert.NotNull(resolverResult.WebHostBuilderFactory);
+            Assert.NotNull(resolverResult.WebHostFactory);
+            Assert.IsAssignableFrom<IWebHostBuilder>(resolverResult.WebHostBuilderFactory(Array.Empty<string>()));
+        }
+
+        [Fact]
+        public void CanFindWebHost_CreateWebHostBuilderPattern()
+        {
+            // Arrange & Act
+            var resolverResult = WebHostFactoryResolver.ResolveWebHostFactory(typeof(IStartupInjectionAssemblyName.Startup).Assembly);
+
+            // Assert
+            Assert.Equal(FactoryResolutionResultKind.Success, resolverResult.ResultKind);
+            Assert.NotNull(resolverResult.WebHostBuilderFactory);
+            Assert.NotNull(resolverResult.WebHostFactory);
+        }
+
+        [Fact]
+        public void CanNotFindWebHostBuilder_BuildWebHostPattern()
+        {
+            // Arrange & Act
+            var resolverResult = WebHostFactoryResolver.ResolveWebHostBuilderFactory(typeof(BuildWebHostPatternTestSite.Startup).Assembly);
+
+            // Assert
+            Assert.Equal(FactoryResolutionResultKind.NoCreateWebHostBuilder, resolverResult.ResultKind);
+            Assert.Null(resolverResult.WebHostBuilderFactory);
+            Assert.Null(resolverResult.WebHostFactory);
+        }
+
+        [Fact]
+        public void CanFindWebHost_BuildWebHostPattern()
+        {
+            // Arrange & Act
+            var resolverResult = WebHostFactoryResolver.ResolveWebHostFactory(typeof(BuildWebHostPatternTestSite.Startup).Assembly);
+
+            // Assert
+            Assert.Equal(FactoryResolutionResultKind.Success, resolverResult.ResultKind);
+            Assert.Null(resolverResult.WebHostBuilderFactory);
+            Assert.NotNull(resolverResult.WebHostFactory);
+        }
+    }
+}

test/TestAssets/BuildWebHostPatternTestSite/BuildWebHostPatternTestSite.csproj

@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>netcoreapp2.0;net461</TargetFrameworks>
+    <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netcoreapp2.0</TargetFrameworks>
+    <OutputType>Exe</OutputType>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Hosting\Microsoft.AspNetCore.Hosting.csproj" />
+    <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.TestHost\Microsoft.AspNetCore.TestHost.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" />
+  </ItemGroup>
+
+</Project>

test/TestAssets/BuildWebHostPatternTestSite/Program.cs

@@ -0,0 +1,16 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Hosting;
+
+namespace BuildWebHostPatternTestSite
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+        }
+
+        public static IWebHost BuildWebHost(string[] args) => null;
+    }
+}

test/TestAssets/BuildWebHostPatternTestSite/Startup.cs

@@ -0,0 +1,19 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Builder;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace BuildWebHostPatternTestSite
+{
+    public class Startup
+    {
+        public void ConfigureServices(IServiceCollection services)
+        {
+        }
+
+        public void Configure(IApplicationBuilder builder)
+        {
+        }
+    }
+}

test/TestAssets/IStartupInjectionAssemblyName/IStartupInjectionAssemblyName.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk.Web">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFrameworks>netcoreapp2.0;net461</TargetFrameworks>

test/TestAssets/IStartupInjectionAssemblyName/Program.cs

@@ -13,8 +13,7 @@ namespace IStartupInjectionAssemblyName
     {
         public static void Main(string[] args)
         {
-            var server = new TestServer(new WebHostBuilder()
+            var server = new TestServer(CreateWebHostBuilder(args));
-                .ConfigureServices(services => services.AddSingleton<IStartup, Startup>()));
 
             // Mimic application startup messages so application deployer knows that the application has started
             Console.WriteLine("Application started. Press Ctrl+C to shut down.");
@@ -22,5 +21,9 @@ namespace IStartupInjectionAssemblyName
 
             Task.Run(async () => Console.WriteLine(await server.CreateClient().GetStringAsync(""))).GetAwaiter().GetResult();
         }
+
+        // Do not change the signature of this method. It's used for tests.
+        private static IWebHostBuilder CreateWebHostBuilder(string [] args) =>
+            new WebHostBuilder().ConfigureServices(services => services.AddSingleton<IStartup, Startup>());
     }
 }

test/TestAssets/IStartupInjectionAssemblyName/Properties/launchSettings.json

@@ -0,0 +1,27 @@
+{
+  "iisSettings": {
+    "windowsAuthentication": false,
+    "anonymousAuthentication": true,
+    "iisExpress": {
+      "applicationUrl": "http://localhost:50801/",
+      "sslPort": 0
+    }
+  },
+  "profiles": {
+    "IIS Express": {
+      "commandName": "IISExpress",
+      "launchBrowser": true,
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "IStartupInjectionAssemblyName": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      },
+      "applicationUrl": "http://localhost:50802/"
+    }
+  }
+}

test/TestAssets/Microsoft.AspNetCore.Hosting.TestSites/Microsoft.AspNetCore.Hosting.TestSites.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk.Web">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFrameworks>netcoreapp2.0;net461</TargetFrameworks>

test/TestAssets/Microsoft.AspNetCore.Hosting.TestSites/Properties/launchSettings.json

@@ -0,0 +1,27 @@
+{
+  "iisSettings": {
+    "windowsAuthentication": false,
+    "anonymousAuthentication": true,
+    "iisExpress": {
+      "applicationUrl": "http://localhost:50800/",
+      "sslPort": 0
+    }
+  },
+  "profiles": {
+    "IIS Express": {
+      "commandName": "IISExpress",
+      "launchBrowser": true,
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "Microsoft.AspNetCore.Hosting.TestSites": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      },
+      "applicationUrl": "http://localhost:50803/"
+    }
+  }
+}