fix build and add batch tests

src/Speckle.Sdk.Dependencies/Serialization/SizeBatchingChannelReader.cs

@@ -13,12 +13,18 @@ public class SizeBatchingChannelReader<T>(
   int batchSize,
   bool singleReader,
   bool syncCont = false
-) : BatchingChannelReader<T, Batch<T>>(source, batchSize, singleReader, syncCont)
+) : BatchingChannelReader<T, Batch<T>>(x => new(x), source, batchSize, singleReader, syncCont)
   where T : IHasSize
 {
   protected override Batch<T> CreateBatch(int capacity) => new(capacity);
 
-  protected override void TrimBatch(Batch<T> batch) => batch.TrimExcess();
+  protected override void TrimBatch(ref Batch<T> batch, bool isVerifiedFull)
+  {
+    if (!isVerifiedFull)
+    {
+      batch.TrimExcess();
+    }
+  }
 
   protected override void AddBatchItem(Batch<T> batch, T item) => batch.Add(item);
 

tests/Speckle.Sdk.Tests.Unit/Serialisation/BatchTests.cs

@@ -0,0 +1,44 @@
+using NUnit.Framework;
+using Shouldly;
+using Speckle.Sdk.Serialisation.V2.Send;
+
+namespace Speckle.Sdk.Tests.Unit.Serialisation;
+
+[TestFixture]
+public class BatchTests
+{
+  private class BatchItem : IHasSize
+  {
+    public BatchItem(int size)
+    {
+      Size = size;
+    }
+
+    public int Size { get; }
+  }
+
+  [Test]
+  public void TestBatchSize_Calc()
+  {
+    var batch = new Batch<BatchItem>(4);
+    batch.Add(new BatchItem(1));
+    batch.Size.ShouldBe(1);
+    batch.Add(new BatchItem(2));
+    batch.Size.ShouldBe(3);
+  }
+
+  [Test]
+  public void TestBatchSize_Trim()
+  {
+    var batch = new Batch<BatchItem>(4);
+    batch.Add(new BatchItem(1));
+    batch.Add(new BatchItem(2));
+    batch.Size.ShouldBe(3);
+
+    batch.Items.Capacity.ShouldBe(4);
+    batch.TrimExcess();
+
+    batch.Items.Capacity.ShouldBe(2);
+    batch.Size.ShouldBe(3);
+  }
+}

tests/Speckle.Sdk.Tests.Unit/Serialisation/SimpleRoundTripTests.cs

@@ -8,6 +8,7 @@
 
 namespace Speckle.Sdk.Tests.Unit.Serialisation;
 
+[TestFixture]
 public class SimpleRoundTripTests
 {
   private IOperations _operations;