Add option to configure the created HttpClient

Changelog.md

@@ -1,5 +1,17 @@
 # Codenizer.HttpClient.Testable Changelog
 
+## 2.7.0.0
+
+Add the option to specify a lambda to configure the `HttpClient` as it's being created by the `TestableHttpClientFactory`.
+
+For example:
+
+```csharp
+_factory.ConfigureClient(
+    "name of client", 
+    httpClient => httpClient.BaseAddress = new Uri("https://example.com"));
+```
+
 ## 2.6.0.0
 
 Downgrade Microsoft.Extensions.Http from 7.0.0 to 6.0.0 for greater compatibility.

Codenizer.HttpClient.Testable.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.0.32002.261
+# Visual Studio Version 17
+VisualStudioVersion = 17.8.34408.163
 MinimumVisualStudioVersion = 15.0.26124.0
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{C0192DBD-4673-4573-BF61-FD0B4EFB7D11}"
 EndProject
@@ -14,6 +14,7 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{61B5BDEC-5FE6-4196-A6A0-566E9012E2A9}"
 	ProjectSection(SolutionItems) = preProject
 		Changelog.md = Changelog.md
+		Directory.Build.props = Directory.Build.props
 		README.md = README.md
 	EndProjectSection
 EndProject

Directory.Build.props

@@ -1,10 +1,10 @@
 
 <Project>
 	<PropertyGroup>
-		<Version>2.6.0.0</Version>
+		<Version>2.7.0.0</Version>
 		<Authors>Sander van Vliet</Authors>
 		<Company>Codenizer BV</Company>
-		<Copyright>2023 Sander van Vliet</Copyright>
+		<Copyright>2024 Sander van Vliet</Copyright>
 	</PropertyGroup>
 	<PropertyGroup>
 		<LangVersion>10</LangVersion>

src/Codenizer.HttpClient.Testable/TestableHttpClientFactory.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Net.Http;
 
 namespace Codenizer.HttpClient.Testable
@@ -8,21 +9,33 @@ namespace Codenizer.HttpClient.Testable
     /// </summary>
     public class TestableHttpClientFactory : IHttpClientFactory
     {
-        private readonly Dictionary<string, TestableMessageHandler> _clientConfigurations = new Dictionary<string, TestableMessageHandler>();
+        private readonly Dictionary<string, TestableMessageHandler> _namedHandlers = new();
+        private readonly Dictionary<string, Action<System.Net.Http.HttpClient>> _clientConfigurations = new();
 
         /// <inheritdoc cref="IHttpClientFactory.CreateClient"/>
         public System.Net.Http.HttpClient CreateClient(string name)
         {
-            if (!_clientConfigurations.ContainsKey(name))
+            System.Net.Http.HttpClient httpClient;
+
+            if (!_namedHandlers.ContainsKey(name))
             {
                 // No client was configured but IHttpClientFactory.CreateClient
                 // requires us to return a new HttpClient instance. So we will
                 // return one but it's going to be backed by a default
                 // TestableMessageHandler. 
-                return new System.Net.Http.HttpClient(new TestableMessageHandler());
+                httpClient = new System.Net.Http.HttpClient(new TestableMessageHandler());
+            }
+            else
+            {
+                httpClient = new System.Net.Http.HttpClient(_namedHandlers[name]);
             }
 
-            return new System.Net.Http.HttpClient(_clientConfigurations[name]);
+            if (_clientConfigurations.ContainsKey(name))
+            {
+                _clientConfigurations[name](httpClient);
+            }
+
+            return httpClient;
         }
 
         /// <summary>
@@ -32,7 +45,21 @@ public System.Net.Http.HttpClient CreateClient(string name)
         /// <param name="messageHandler">The <see cref="TestableMessageHandler"/> instance that should be used for the client name</param>
         public void ConfigureClient(string name, TestableMessageHandler messageHandler)
         {
-            _clientConfigurations.Add(name, messageHandler);
+            _namedHandlers.Add(name, messageHandler);
+        }
+
+        /// <summary>
+        /// Configure a client name to return a <see cref="HttpClient"/> with a <see cref="TestableMessageHandler"/> and configure the <see cref="HttpClient"/> instance with defaults
+        /// </summary>
+        /// <param name="name">The name of the <see cref="HttpClient"/> as requested by <see cref="CreateClient"/></param>
+        /// <param name="configure">A lambda to configure the created <see cref="HttpClient"/></param>
+        /// <returns>The <see cref="TestableMessageHandler"/> instance that will be used for the client name</returns>
+        public TestableMessageHandler ConfigureClient(string name, Action<System.Net.Http.HttpClient> configure)
+        {
+            _clientConfigurations.Add(name, configure);
+            var handler = ConfigureClient(name);
+
+            return handler;
         }
 
         /// <summary>
@@ -43,7 +70,7 @@ public void ConfigureClient(string name, TestableMessageHandler messageHandler)
         public TestableMessageHandler ConfigureClient(string name)
         {
             var messageHandler = new TestableMessageHandler();
-            _clientConfigurations.Add(name, messageHandler);
+            _namedHandlers.Add(name, messageHandler);
             return messageHandler;
         }
     }

test/Codenizer.HttpClient.Testable.Tests.Unit/WhenConfiguringHandlerThroughHttpClientFactory.cs

@@ -0,0 +1,69 @@
+using System;
+using System.Net.Http;
+using System.Reflection;
+using FluentAssertions;
+using Xunit;
+
+namespace Codenizer.HttpClient.Testable.Tests.Unit
+{
+    public class WhenConfiguringHandlerThroughHttpClientFactory
+    {
+        private readonly TestableHttpClientFactory _factory = new();
+        private const string ClientName = "test client name";
+
+        [Fact]
+        public void GivenClientNameWasNotConfigured_NewHandlerIsRegistered()
+        {
+            var client = _factory.CreateClient(ClientName);
+
+            client
+                .Should()
+                .NotBeNull();
+        }
+
+        [Fact]
+        public void GivenClientNameWasConfigured_ClientUsesConfiguredHandler()
+        {
+            var handler = _factory.ConfigureClient(ClientName);
+
+            var client = _factory.CreateClient(ClientName);
+
+            TheHandlerOf(client)
+                .Should()
+                .Be(handler);
+        }
+
+        [Fact]
+        public void GivenClientWasConfiguredWithSpecificHandler_ClientIsUsingSpecifiedHandler()
+        {
+            var handler = new TestableMessageHandler();
+            _factory.ConfigureClient(ClientName, handler);
+
+            var client = _factory.CreateClient(ClientName);
+
+            TheHandlerOf(client)
+                .Should()
+                .Be(handler);
+        }
+
+        [Fact]
+        public void GivenClientNameWasConfiguredWithClientConfiguration_ConfigurationIsAppliedToClient()
+        {
+            _factory.ConfigureClient(ClientName, client => client.BaseAddress = new Uri("https://example.com"));
+
+            var client = _factory.CreateClient(ClientName);
+
+            client
+                .BaseAddress
+                .Should()
+                .Be(new Uri("https://example.com"));
+        }
+
+        private HttpMessageHandler? TheHandlerOf(System.Net.Http.HttpClient client)
+        {
+            var field = typeof(HttpMessageInvoker).GetField("_handler", BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.GetField);
+
+            return field?.GetValue(client) as HttpMessageHandler;
+        }
+    }
+}