Adding test to verify multi threaded random support, and adjusting implementation to use ThreadStatic for NET3X, ThreadLocal for anything else. Fixes bug with getting null Random instance when accessing on the second created thread, due to ThreadLocal variable only being instantiated once in the static constructor instead of once per thread.

Author: blmeyers

ObjectFiller.Test/RandomAccessTest.cs

@@ -0,0 +1,51 @@
+namespace ObjectFiller.Test
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Threading.Tasks;
+
+        using Xunit;
+
+    using ObjectFiller.Test.TestPoco.Library;
+    using ObjectFiller.Test.TestPoco.Person;
+
+    using Tynamix.ObjectFiller;
+
+
+    public class RandomAccessTest
+    {
+        [Fact]
+        public void GetRandomIntOnDifferentThreadsGetsDifferentResults()
+        {
+            var numberToGenerate = 1000;
+            var intRange = new IntRange(1, 10);
+            var task1 = Task.Factory.StartNew(() =>
+                {
+                    var taskResults = new List<int>();
+                    for (int i = 0; i < numberToGenerate; ++i)
+                    {
+                        taskResults.Add(Randomizer<int>.Create(intRange));
+                    }
+                    return taskResults;
+                },
+                TaskCreationOptions.LongRunning
+            );
+            var task2 = Task.Factory.StartNew(() =>
+                {
+                    var taskResults = new List<int>();
+                    for (int i = 0; i < numberToGenerate; ++i)
+                    {
+                        taskResults.Add(Randomizer<int>.Create(intRange));
+                    }
+                    return taskResults;
+                },
+                TaskCreationOptions.LongRunning
+            );
+            var results = Task.WhenAll(task1, task2).Result;
+            List<int> firstResults = results[0];
+            List<int> secondResults = results[1];
+            Assert.NotEqual(firstResults, secondResults);
+        }
+    }
+}

ObjectFiller/Random.cs

@@ -19,24 +19,47 @@ namespace Tynamix.ObjectFiller
     /// </summary>
     internal static class Random
     {
+
+        private static int RandomSeed;
         /// <summary>
+        /// Initializes static members of the <see cref="Random"/> class.
         /// A instance of <see cref="Random"/>
         /// </summary>
-        [ThreadStatic]
-        private static readonly System.Random Rnd;
+        static Random()
+        {
+            RandomSeed = Environment.TickCount;
+        }
 
+#if NET3X
         /// <summary>
-        /// Initializes static members of the <see cref="Random"/> class.
+        /// A instance of <see cref="Random"/>
         /// </summary>
-        static Random()
+        [ThreadStatic]
+        private static System.Random RndStorage;
+
+        private static System.Random Rnd
         {
-#if NETSTD
-            Rnd = new System.Random();
+            get
+            {
+                if (RndStorage == null)
+                {
+                    RndStorage = new System.Random(Interlocked.Increment(ref RandomSeed));
+                }
+                return RndStorage;
+            }
+        }
 #else
-            int seed = Environment.TickCount;
-            Rnd = new System.Random(Interlocked.Increment(ref seed));
-#endif
+        private static readonly ThreadLocal<System.Random> RndStorage = new ThreadLocal<System.Random>(() =>
+            new System.Random(Interlocked.Increment(ref RandomSeed)));
+
+        /// <summary>
+        /// A instance of <see cref="Random"/>
+        /// </summary>
+        private static System.Random Rnd
+        {
+            get { return RndStorage.Value; }
         }
+#endif
 
         /// <summary>
         /// Returns a nonnegative number