Add support for WebApplicationFactory instances (#11)

Author: Kralizek

src/AspNetCore.WebApplicationFactory/AspNetCoreWebApplicationFactoryFixtureExtensions.cs

@@ -13,17 +13,30 @@ public static class AspNetCoreWebApplicationFactoryFixtureExtensions
         public static IFixture AddWebApplicationFactorySupport<TEntryPoint>(this IFixture fixture, Action<IWebHostBuilder>? configuration = null)
             where TEntryPoint : class
         {
-            return AddWebApplicationFactorySupport<WebApplicationFactory<TEntryPoint>, TEntryPoint>(fixture, configuration ?? EmptyAction);
+            return AddWebApplicationFactorySupport<WebApplicationFactory<TEntryPoint>, TEntryPoint>(fixture, null, configuration ?? EmptyAction);
+        }
+        
+        public static IFixture AddWebApplicationFactorySupport<TEntryPoint>(this IFixture fixture, WebApplicationFactory<TEntryPoint> instance)
+            where TEntryPoint : class
+        {
+            return AddWebApplicationFactorySupport<WebApplicationFactory<TEntryPoint>, TEntryPoint>(fixture, instance, EmptyAction);
         }
 
         public static IFixture AddWebApplicationFactorySupport<TFactory, TEntryPoint>(this IFixture fixture)
             where TFactory : WebApplicationFactory<TEntryPoint>, new()
             where TEntryPoint : class
         {
-            return AddWebApplicationFactorySupport<TFactory, TEntryPoint>(fixture, EmptyAction);
+            return AddWebApplicationFactorySupport<TFactory, TEntryPoint>(fixture, null, EmptyAction);
+        }
+
+        public static IFixture AddWebApplicationFactorySupport<TFactory, TEntryPoint>(this IFixture fixture, TFactory instance)
+            where TFactory : WebApplicationFactory<TEntryPoint>, new()
+            where TEntryPoint : class
+        {
+            return AddWebApplicationFactorySupport<TFactory, TEntryPoint>(fixture, instance, EmptyAction);
         }
 
-        private static IFixture AddWebApplicationFactorySupport<TFactory, TEntryPoint>(this IFixture fixture, Action<IWebHostBuilder> configuration)
+        private static IFixture AddWebApplicationFactorySupport<TFactory, TEntryPoint>(this IFixture fixture, TFactory? instance, Action<IWebHostBuilder> configuration)
             where TFactory : WebApplicationFactory<TEntryPoint>, new()
             where TEntryPoint : class
         {
@@ -32,7 +45,7 @@ private static IFixture AddWebApplicationFactorySupport<TFactory, TEntryPoint>(t
                 throw new ArgumentNullException(nameof(fixture));
             }
 
-            fixture.Customize(new WebApplicationFactoryCustomization<TFactory, TEntryPoint>(configuration));
+            fixture.Customize(new WebApplicationFactoryCustomization<TFactory, TEntryPoint>(instance, configuration));
 
             return fixture;
         }

src/AspNetCore.WebApplicationFactory/Internal/WebApplicationFactoryCustomization.cs

@@ -9,17 +9,30 @@ public class WebApplicationFactoryCustomization<TFactory, TEntryPoint> : ICustom
         where TFactory : WebApplicationFactory<TEntryPoint>, new()
         where TEntryPoint : class
     {
+        private readonly TFactory? _instance;
         private readonly Action<IWebHostBuilder> _configuration;
 
-        public WebApplicationFactoryCustomization(Action<IWebHostBuilder> configuration)
+        public WebApplicationFactoryCustomization(TFactory? instance, Action<IWebHostBuilder> configuration)
         {
+            _instance = instance;
             _configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
         }
 
         public void Customize(IFixture fixture)
         {
-            fixture.Inject(new TFactory().WithWebHostBuilder(_configuration));
-
+            if (_instance is not null)
+            {
+                fixture.Inject<TFactory>(_instance);
+            }
+            else if (typeof(TFactory) == typeof(WebApplicationFactory<TEntryPoint>))
+            {
+                fixture.Inject(new TFactory().WithWebHostBuilder(_configuration));
+            }
+            else
+            {
+                fixture.Inject(new TFactory());
+            }
+            
             fixture.Customizations.Add(new HttpClientSpecimenBuilder<TFactory, TEntryPoint>());
         }
     }

tests/Tests.AspNetCore.WebApplicationFactory/AspNetCoreWebApplicationFactoryFixtureExtensionsTests.cs

@@ -2,36 +2,94 @@
 using Kralizek.AutoFixture.Extensions.Internal;
 using Microsoft.AspNetCore.Mvc.Testing;
 using NUnit.Framework;
+using TestWebSite;
+
 // ReSharper disable InvokeAsExtensionMethod
 
 namespace Tests
 {
     public class AspNetCoreWebApplicationFactoryFixtureExtensionsTests
     {
+        [Test]
+        public void AddWebApplicationFactorySupport_throws_if_fixture_is_null()
+        {
+            Assert.That(() => AspNetCoreWebApplicationFactoryFixtureExtensions.AddWebApplicationFactorySupport<Startup>(null!), Throws.ArgumentNullException);
+        }
+        
+        [Test]
+        public void AddWebApplicationFactorySupport_with_custom_factory_throws_if_fixture_is_null()
+        {
+            Assert.That(() => AspNetCoreWebApplicationFactoryFixtureExtensions.AddWebApplicationFactorySupport<CustomWebApplicationFactory, Startup>(null!), Throws.ArgumentNullException);
+        }
+
+        [Test]
+        public void AddWebApplicationFactorySupport_with_instance_throws_if_fixture_is_null()
+        {
+            var instance = new WebApplicationFactory<Startup>();
+            
+            Assert.That(() => AspNetCoreWebApplicationFactoryFixtureExtensions.AddWebApplicationFactorySupport(null!, instance), Throws.ArgumentNullException);
+        }
+        
+        [Test]
+        public void AddWebApplicationFactorySupport_with_custom_factory_instance_throws_if_fixture_is_null()
+        {
+            var instance = new CustomWebApplicationFactory();
+            
+            Assert.That(() => AspNetCoreWebApplicationFactoryFixtureExtensions.AddWebApplicationFactorySupport<CustomWebApplicationFactory, Startup>(null!, instance), Throws.ArgumentNullException);
+        }
+        
         [Test, CustomAutoData]
         public void AddWebApplicationFactorySupport_registers_customization(IFixture fixture)
         {
-            AspNetCoreWebApplicationFactoryFixtureExtensions.AddWebApplicationFactorySupport<TestWebSite.Startup>(fixture);
+            AspNetCoreWebApplicationFactoryFixtureExtensions.AddWebApplicationFactorySupport<Startup>(fixture);
 
             Assert.Multiple(() =>
             {
-                Assert.That(() => fixture.Create<WebApplicationFactory<TestWebSite.Startup>>(), Throws.Nothing);
+                Assert.That(() => fixture.Create<WebApplicationFactory<Startup>>(), Throws.Nothing);
 
-                Assert.That(fixture.Customizations, Has.Exactly(1).InstanceOf<HttpClientSpecimenBuilder<WebApplicationFactory<TestWebSite.Startup>, TestWebSite.Startup>>());
+                Assert.That(fixture.Customizations, Has.Exactly(1).InstanceOf<HttpClientSpecimenBuilder<WebApplicationFactory<Startup>, Startup>>());
             });
         }
 
         [Test, CustomAutoData]
         public void AddWebApplicationFactorySupport_registers_customization_with_custom_factory(IFixture fixture)
         {
-            AspNetCoreWebApplicationFactoryFixtureExtensions.AddWebApplicationFactorySupport<CustomWebApplicationFactory, TestWebSite.Startup>(fixture);
+            AspNetCoreWebApplicationFactoryFixtureExtensions.AddWebApplicationFactorySupport<CustomWebApplicationFactory, Startup>(fixture);
+
+            Assert.Multiple(() =>
+            {
+                Assert.That(() => fixture.Create<CustomWebApplicationFactory>(), Throws.Nothing);
+
+                Assert.That(fixture.Customizations, Has.Exactly(1).InstanceOf<HttpClientSpecimenBuilder<CustomWebApplicationFactory, Startup>>());
+            });
+        }
+        
+        [Test, CustomAutoData]
+        public void AddWebApplicationFactorySupport_registers_customization_with_instance(IFixture fixture)
+        {
+            var instance = new CustomWebApplicationFactory();
+            
+            AspNetCoreWebApplicationFactoryFixtureExtensions.AddWebApplicationFactorySupport<CustomWebApplicationFactory, Startup>(fixture, instance);
 
             Assert.Multiple(() =>
             {
+               
                 Assert.That(() => fixture.Create<CustomWebApplicationFactory>(), Throws.Nothing);
 
-                Assert.That(fixture.Customizations, Has.Exactly(1).InstanceOf<HttpClientSpecimenBuilder<CustomWebApplicationFactory, TestWebSite.Startup>>());
+                Assert.That(fixture.Customizations, Has.Exactly(1).InstanceOf<HttpClientSpecimenBuilder<CustomWebApplicationFactory, Startup>>());
             });
         }
+
+        [Test, CustomAutoData]
+        public void AddWebApplicationFactorySupport_returns_registered_instance(IFixture fixture)
+        {
+            var instance = new CustomWebApplicationFactory();
+            
+            AspNetCoreWebApplicationFactoryFixtureExtensions.AddWebApplicationFactorySupport<CustomWebApplicationFactory, Startup>(fixture, instance);
+
+            var factory = fixture.Create<CustomWebApplicationFactory>();
+            
+            Assert.That(factory, Is.SameAs(instance));
+        }
     }
 }

tests/Tests.AspNetCore.WebApplicationFactory/Integration/CustomWebFactoryIntegrationTests.cs

@@ -4,7 +4,6 @@
 using System.Threading.Tasks;
 using AutoFixture;
 using AutoFixture.NUnit3;
-using Microsoft.AspNetCore.TestHost;
 using NUnit.Framework;
 
 namespace Tests.Integration

tests/Tests.AspNetCore.WebApplicationFactory/Integration/InstanceCustomWebFactoryIntegrationTests.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Threading.Tasks;
+using AutoFixture;
+using AutoFixture.NUnit3;
+using Microsoft.AspNetCore.TestHost;
+using NUnit.Framework;
+
+namespace Tests.Integration
+{
+    [TestFixture]
+    public class InstanceCustomWebFactoryIntegrationTests
+    {
+        [AttributeUsage(AttributeTargets.Method)]
+        public class TestAutoDataAttribute : AutoDataAttribute
+        {
+            public TestAutoDataAttribute() : base(() => new Fixture().AddWebApplicationFactorySupport<CustomWebApplicationFactory, TestWebSite.Startup>(new CustomWebApplicationFactory())) { }
+        }
+
+        [Test]
+        public async Task Should_work_with_no_auto_data_attribute()
+        {
+            var instance = new CustomWebApplicationFactory();
+            
+            var fixture = new Fixture().AddWebApplicationFactorySupport<CustomWebApplicationFactory, TestWebSite.Startup>(instance);
+
+            var message = fixture.Create<string>();
+
+            var http = fixture.Create<HttpClient>();
+
+            var response = await http.PostAsync("/", new FormUrlEncodedContent(new Dictionary<string, string> { ["message"] = message }));
+
+            response.EnsureSuccessStatusCode();
+
+            var responseContent = await response.Content.ReadAsStringAsync();
+
+            Assert.That(responseContent, Is.EqualTo(message));
+        }
+
+        [Test, AutoData]
+        public async Task Should_work_with_basic_auto_data_attribute(IFixture fixture, string message)
+        {
+            var instance = new CustomWebApplicationFactory();
+            
+            fixture.AddWebApplicationFactorySupport<CustomWebApplicationFactory, TestWebSite.Startup>(instance);
+
+            var http = fixture.Create<HttpClient>();
+
+            var response = await http.PostAsync("/", new FormUrlEncodedContent(new Dictionary<string, string> { ["message"] = message }));
+
+            response.EnsureSuccessStatusCode();
+
+            var responseContent = await response.Content.ReadAsStringAsync();
+
+            Assert.That(responseContent, Is.EqualTo(message));
+        }
+
+        [Test, TestAutoData]
+        public async Task Should_work_with_custom_auto_data_attribute(HttpClient http, string message)
+        {
+            var response = await http.PostAsync("/", new FormUrlEncodedContent(new Dictionary<string, string> { ["message"] = message }));
+
+            response.EnsureSuccessStatusCode();
+
+            var responseContent = await response.Content.ReadAsStringAsync();
+
+            Assert.That(responseContent, Is.EqualTo(message));
+        }
+    }
+}

tests/Tests.AspNetCore.WebApplicationFactory/Integration/InstanceStandardWebFactoryIntegrationTests.cs

@@ -0,0 +1,73 @@
+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Threading.Tasks;
+using AutoFixture;
+using AutoFixture.NUnit3;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.AspNetCore.TestHost;
+using NUnit.Framework;
+using TestWebSite;
+
+namespace Tests.Integration
+{
+    [TestFixture]
+    public class InstanceStandardWebFactoryIntegrationTests
+    {
+        [AttributeUsage(AttributeTargets.Method)]
+        public class TestAutoDataAttribute : AutoDataAttribute
+        {
+            public TestAutoDataAttribute() : base(() => new Fixture().AddWebApplicationFactorySupport(new WebApplicationFactory<Startup>())) { }
+        }
+
+        [Test]
+        public async Task Should_work_with_no_auto_data_attribute()
+        {
+            var instance = new WebApplicationFactory<Startup>();
+            
+            var fixture = new Fixture().AddWebApplicationFactorySupport(instance);
+
+            var message = fixture.Create<string>();
+
+            var http = fixture.Create<HttpClient>();
+
+            var response = await http.PostAsync("/", new FormUrlEncodedContent(new Dictionary<string, string> { ["message"] = message }));
+
+            response.EnsureSuccessStatusCode();
+
+            var responseContent = await response.Content.ReadAsStringAsync();
+
+            Assert.That(responseContent, Is.EqualTo(message));
+        }
+
+        [Test, AutoData]
+        public async Task Should_work_with_basic_auto_data_attribute(IFixture fixture, string message)
+        {
+            var instance = new WebApplicationFactory<Startup>();
+            
+            fixture.AddWebApplicationFactorySupport(instance);
+
+            var http = fixture.Create<HttpClient>();
+
+            var response = await http.PostAsync("/", new FormUrlEncodedContent(new Dictionary<string, string> { ["message"] = message }));
+
+            response.EnsureSuccessStatusCode();
+
+            var responseContent = await response.Content.ReadAsStringAsync();
+
+            Assert.That(responseContent, Is.EqualTo(message));
+        }
+
+        [Test, TestAutoData]
+        public async Task Should_work_with_custom_auto_data_attribute(HttpClient http, string message)
+        {
+            var response = await http.PostAsync("/", new FormUrlEncodedContent(new Dictionary<string, string> { ["message"] = message }));
+
+            response.EnsureSuccessStatusCode();
+
+            var responseContent = await response.Content.ReadAsStringAsync();
+
+            Assert.That(responseContent, Is.EqualTo(message));
+        }
+    }
+}