CreateBigSourceDataWithBlockSize() will yield only items count + block size if the number of blocks fits max array size.

Recyclable.Collections.TestData/RecyclableLongListTestData.cs

@@ -189,10 +189,13 @@ namespace Recyclable.Collections.TestData
 			long itemsCount = Array.MaxLength;
 			using var testData = CreateTestData(itemsCount).ToRecyclableLongList();
 			foreach (var blockSize in BlockSizeVariants)
+			{
+				if (IsValidBlockSize(itemsCount, blockSize))
 				{
 					yield return ($"long[{itemsCount}]", testData, itemsCount, blockSize);					
 				}
 			}
+		}
 
 		public static IEnumerable<(string TestCase, IEnumerable<long> TestData, long ItemsCount, int BlockSize, IEnumerable<(long ItemIndex, long RangeStartItemIndex, long RangeItemsCount)> ItemIndexesWithRange)> CreateBigSourceDataWithOutOfRangeItemIndexesWithRange()
 		{
@@ -439,7 +442,7 @@ namespace Recyclable.Collections.TestData
 				yield return index;
 			}
 		}
-		public static bool IsValidBlockSize(long itemsCount, long blockSize) => itemsCount is < 1024 || blockSize is > 8;
+		public static bool IsValidBlockSize(long itemsCount, long blockSize) => itemsCount is < 1024 || (itemsCount / blockSize + (itemsCount % blockSize > 0 ? 1 : 0) <= Array.MaxLength);
 
 		public static IEnumerable<int> BlockSizeVariants { get; }= new int[]
 		{