test(resourcemanager): mock test for cae support (#47138)

* add a mock test case to verify mgmt SDKs should support CAE
* add invalid cae response case

resolve #47137

---------

Co-authored-by: Mingzhe Huang (from Dev Box) <[email protected]>

sdk/resourcemanager/Azure.ResourceManager/tests/Unit/HttpPipelineTests.cs

@@ -0,0 +1,79 @@
+using Azure.Core.TestFramework;
+using NUnit.Framework;
+
+namespace Azure.ResourceManager.Tests.Unit
+{
+    [Parallelizable]
+    public class HttpPipelineTests
+    {
+        [Test]
+        public void CaeSupport()
+        {
+            int callCount = 0;
+            var option = new ArmClientOptions()
+            {
+                // we mock a CAE challenge before the actual response is returned
+                Transport = new MockTransport((r) =>
+                {
+                    callCount++;
+
+                    if (callCount == 1)
+                    {
+                        return new MockResponse(401).WithHeader("WWW-Authenticate", CaeChallenge);
+                    }
+                    var response = new MockResponse(200);
+                    response.SetContent(SubscriptionData);
+                    return response;
+                })
+            };
+            var client = new ArmClient(new MockCredential(), "83aa47df-e3e9-49ff-877b-94304bf3d3ad", option);
+            var subscription = client.GetDefaultSubscription();
+            Assert.AreEqual(2, callCount);
+            Assert.AreEqual("83aa47df-e3e9-49ff-877b-94304bf3d3ad", subscription.Data.Id.SubscriptionId);
+            Assert.AreEqual("Subscription2", subscription.Data.DisplayName);
+            Assert.IsEmpty(subscription.Data.Tags);
+        }
+
+        [Test]
+        public void InvalidCaeResponse()
+        {
+            int callCount = 0;
+            var option = new ArmClientOptions()
+            {
+                // we mock a CAE challenge before the actual response is returned
+                Transport = new MockTransport((r) =>
+                {
+                    callCount++;
+
+                    if (callCount == 1)
+                    {
+                        return new MockResponse(401).WithHeader("WWW-Authenticate", InvalidCaeChallenge);
+                    }
+                    var response = new MockResponse(200);
+                    response.SetContent(SubscriptionData);
+                    return response;
+                })
+            };
+            var client = new ArmClient(new MockCredential(), "83aa47df-e3e9-49ff-877b-94304bf3d3ad", option);
+            Assert.Throws<RequestFailedException>(() => client.GetDefaultSubscription());
+            Assert.AreEqual(1, callCount);
+        }
+
+        private const string CaeChallenge = """Bearer realm="", error_description="Continuous access evaluation resulted in challenge", error="insufficient_claims", claims="eyJhY2Nlc3NfdG9rZW4iOnsibmJmIjp7ImVzc2VudGlhbCI6dHJ1ZSwgInZhbHVlIjoiMTcyNjI1ODEyMiJ9fX0=" """;
+
+        private const string InvalidCaeChallenge = """Bearer realm="", error_description="", error="insufficient_claims", claims="" """;
+
+        private const string SubscriptionData = @"{
+  ""id"": ""/subscriptions/83aa47df-e3e9-49ff-877b-94304bf3d3ad"",
+  ""authorizationSource"": ""Legacy"",
+  ""subscriptionId"": ""83aa47df-e3e9-49ff-877b-94304bf3d3ad"",
+  ""displayName"": ""Subscription2"",
+  ""state"": ""Enabled"",
+  ""subscriptionPolicies"": {
+    ""locationPlacementId"": ""Internal_2014-09-01"",
+    ""quotaId"": ""Internal_2014-09-01"",
+    ""spendingLimit"": ""Off""
+  }
+}";
+    }
+}