Test fix.

test/OpenTelemetry.Extensions.Hosting.Tests/HostingTracerExtensionTests.cs

@@ -183,12 +183,33 @@ public void AddOpenTelemetryTracerProvider_ConfigureCallbacksUsingExtensions()
         }
 
         [Fact]
-        public void AddOpenTelemetryTracerProvider_Idempotent()
+        public void AddOpenTelemetryTracing_SingleBuilderAllowed()
         {
             var services = new ServiceCollection();
 
-            services.AddOpenTelemetryTracing(builder => builder.AddSource("TestSource"));
+            services.AddOpenTelemetryTracing(builder => builder.AddSource("TestSourceBuilder1"));
             services.AddOpenTelemetryTracing();
+            services.AddOpenTelemetryTracing();
+            services.AddOpenTelemetryTracing();
+
+            using var serviceProvider = services.BuildServiceProvider();
+
+            var builders = serviceProvider.GetServices<TracerProviderBuilderHosting>();
+
+            Assert.Single(builders);
+
+            var provider = serviceProvider.GetRequiredService<TracerProvider>();
+
+            Assert.NotNull(provider);
+        }
+
+        [Fact]
+        public void AddOpenTelemetryTracing_MultipleBuildersThrowsNotSupported()
+        {
+            var services = new ServiceCollection();
+
+            services.AddOpenTelemetryTracing(builder => builder.AddSource("TestSourceBuilder1"));
+            services.AddOpenTelemetryTracing(builder => builder.AddSource("TestSourceBuilder2"));
 
             using var serviceProvider = services.BuildServiceProvider();