fix: users for alias not balanced across threads

bindings/src/Capgemini.PowerApps.SpecFlowBindings/Configuration/TestConfiguration.cs

@@ -4,6 +4,7 @@
     using System.Collections.Generic;
     using System.Configuration;
     using System.Linq;
+    using Capgemini.PowerApps.SpecFlowBindings.Extensions;
     using YamlDotNet.Serialization;
 
     /// <summary>
@@ -82,7 +83,7 @@ private Dictionary<string, IEnumerator<UserConfiguration>> UserEnumerators
                             .Distinct()
                             .ToDictionary(
                                 alias => alias,
-                                alias => this.Users.Where(u => u.Alias == alias).GetEnumerator());
+                                alias => this.GetUserEnumerator(alias));
                     }
                 }
 
@@ -119,7 +120,7 @@ public UserConfiguration GetUser(string userAlias, bool useCurrentUser = true)
                     var aliasEnumerator = this.UserEnumerators[userAlias];
                     if (!aliasEnumerator.MoveNext())
                     {
-                        this.UserEnumerators[userAlias] = this.Users.Where(u => u.Alias == userAlias).GetEnumerator();
+                        this.UserEnumerators[userAlias] = this.GetUserEnumerator(userAlias);
                         aliasEnumerator = this.UserEnumerators[userAlias];
                         aliasEnumerator.MoveNext();
                     }
@@ -149,5 +150,10 @@ internal void Flush()
         {
             CurrentUsers.Clear();
         }
+
+        private IEnumerator<UserConfiguration> GetUserEnumerator(string alias)
+        {
+            return this.Users.Where(u => u.Alias == alias).ToList().Shuffle().GetEnumerator();
+        }
     }
 }

bindings/src/Capgemini.PowerApps.SpecFlowBindings/Extensions/IListExtensions.cs

@@ -0,0 +1,35 @@
+namespace Capgemini.PowerApps.SpecFlowBindings.Extensions
+{
+    using System;
+    using System.Collections.Generic;
+
+    /// <summary>
+    /// Extensions for <see cref="IList{T}"/>.
+    /// </summary>
+    internal static class IListExtensions
+    {
+        private static readonly Random Rand = new Random();
+
+        /// <summary>
+        /// Randomises the order of a list.
+        /// </summary>
+        /// <typeparam name="T">The type of list items.</typeparam>
+        /// <param name="list">The list.</param>
+        /// <returns>The shuffled list.</returns>
+        internal static IList<T> Shuffle<T>(this IList<T> list)
+        {
+            var n = list.Count;
+
+            while (n > 1)
+            {
+                n--;
+                var k = Rand.Next(n + 1);
+                T value = list[k];
+                list[k] = list[n];
+                list[n] = value;
+            }
+
+            return list;
+        }
+    }
+}