adding unit tests

Author: Sophia Tevosyan

src/Worker/Grpc/ExtendedSessionsCache.cs

@@ -30,7 +30,7 @@ public void Dispose()
     /// This specifies how often the cache checks for stale items, and evicts them.
     /// </param>
     /// <returns>The IMemoryCache that holds the cached <see cref="ExtendedSessionState"/>.</returns>
-    internal MemoryCache GetOrInitializeCache(double expirationScanFrequencyInSeconds)
+    public MemoryCache GetOrInitializeCache(double expirationScanFrequencyInSeconds)
     {
         this.extendedSessions ??= new MemoryCache(new MemoryCacheOptions
         {
@@ -39,4 +39,13 @@ internal MemoryCache GetOrInitializeCache(double expirationScanFrequencyInSecond
 
         return this.extendedSessions;
     }
+
+    /// <summary>
+    /// Returns whether or not the cache has been initialized.
+    /// </summary>
+    /// <returns>True if the cache has been initialized, false otherwise.</returns>
+    public bool IsInitialized()
+    {
+        return this.extendedSessions is not null;
+    }
 }

src/Worker/Grpc/GrpcOrchestrationRunner.cs

@@ -175,17 +175,20 @@ public static string LoadAndRun(
         bool requiresHistory = false;
         double extendedSessionIdleTimeoutInSeconds = 0;
         MemoryCache? extendedSessions = null;
-
-        if (properties.TryGetValue("ExtendedSession", out object? isExtendedSessionObj)
-            && isExtendedSessionObj is bool isExtendedSession
-            && isExtendedSession
-            && properties.TryGetValue("ExtendedSessionIdleTimeoutInSeconds", out object? extendedSessionIdleTimeoutObj)
+
+        if (properties.TryGetValue("ExtendedSessionIdleTimeoutInSeconds", out object? extendedSessionIdleTimeoutObj)
             && extendedSessionIdleTimeoutObj is double extendedSessionIdleTimeout
             && extendedSessionIdleTimeout >= 0)
         {
             extendedSessionIdleTimeoutInSeconds = extendedSessionIdleTimeout;
             extendedSessions = extendedSessionsCache.GetOrInitializeCache(extendedSessionIdleTimeoutInSeconds);
+        }
 
+        if (properties.TryGetValue("ExtendedSession", out object? isExtendedSessionObj)
+            && isExtendedSessionObj is bool isExtendedSession
+            && isExtendedSession
+            && extendedSessions != null)
+        {
             if (extendedSessions.TryGetValue(request.InstanceId, out ExtendedSessionState? extendedSessionState) && extendedSessionState is not null)
             {
                 OrchestrationRuntimeState runtimeState = extendedSessionState!.RuntimeState;