A:初版

test/NetClient.Test/Tests/NetClientRetryTests.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Net;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
+using NetClient.Abstractions;
+using NetClient.DependencyInjection;
+
+namespace NetClient.Test.Tests;
+
+[TestClass]
+public class NetClientRetryTests
+{
+    [TestMethod]
+    public async Task Retry_On_429_Then_Succeed()
+    {
+        var services = new ServiceCollection();
+        var attempts = 0;
+
+        var builder = services.AddNetClient(opt =>
+        {
+            opt.BaseAddress = new Uri("https://retry.test");
+            opt.Retry.Enabled = true;
+            opt.Retry.MaxRetryAttempts = 2;
+            opt.Retry.FirstDelay = TimeSpan.FromMilliseconds(5);
+            opt.Retry.Handle429 = true;
+        });
+
+        builder.ConfigurePrimaryHttpMessageHandler(() => new TestDoubles.TestHttpMessageHandler(req =>
+        {
+            attempts++;
+            if (attempts == 1)
+            {
+                return Task.FromResult(TestDoubles.TestHttpMessageHandler.Text(HttpStatusCode.TooManyRequests, "busy"));
+            }
+            return Task.FromResult(TestDoubles.TestHttpMessageHandler.Text(HttpStatusCode.OK, "ok"));
+        }));
+
+        var sp = services.BuildServiceProvider();
+        var client = sp.GetRequiredService<IHttpClient>();
+
+        var result = await client.GetStringAsync("/ping");
+
+        Assert.AreEqual("ok", result);
+        Assert.AreEqual(2, attempts);
+    }
+}
+