Added PlaybackOnlyAttribute

sdk/core/Azure.Core.TestFramework/src/PlaybackOnlyAttribute.cs

@@ -0,0 +1,46 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using NUnit.Framework;
+using NUnit.Framework.Interfaces;
+using NUnit.Framework.Internal;
+
+namespace Azure.Core.TestFramework
+{
+    /// <summary>
+    /// Attribute on test assemblies, classes, or methods that run only against playback resources.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Class | AttributeTargets.Assembly, AllowMultiple = true, Inherited = true)]
+    public class PlaybackOnlyAttribute : NUnitAttribute, IApplyToTest
+    {
+        private readonly string _reason;
+
+        /// <summary>
+        /// Constructs the attribute giving a reason the associated tests is playback only.
+        /// </summary>
+        public PlaybackOnlyAttribute(string reason)
+        {
+            _reason = reason;
+        }
+
+        /// <summary>
+        /// Modifies the <paramref name="test"/> by adding categories to it and changing the run state as needed.
+        /// </summary>
+        /// <param name="test">The <see cref="Test"/> to modify.</param>
+        public void ApplyToTest(Test test)
+        {
+            test.Properties.Add("Category", "Playback");
+
+            if (test.RunState != RunState.NotRunnable)
+            {
+                RecordedTestMode mode = RecordedTestUtilities.GetModeFromEnvironment();
+                if (mode != RecordedTestMode.Playback)
+                {
+                    test.RunState = RunState.Ignored;
+                    test.Properties.Set("_SKIPREASON", $"Playback tests will not run when AZURE_TEST_MODE is {mode}.  This test was skipped for the following reason: {_reason}");
+                }
+            }
+        }
+    }
+}