Transfer verb: drop the redundant pre-check, let range, step length and quantity edges show in tests

TryStore already takes all of a part or none, so the pre-check in TryTransferItem changed nothing observable.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Assets/Scripts/ServerShared/CargoTransfer.cs

@@ -94,7 +94,7 @@ public static class CargoTransfer
                 order.Budget -= 1;
                 order.Remaining--;
             }
-            if (giver.Giving == order && order.Remaining == 0) End(giver, GiveEnd.Done);
+            if (order.Remaining == 0) End(giver, GiveEnd.Done);
         }
     }
 

Assets/Scripts/ServerShared/Entity.cs

@@ -2664,17 +2664,13 @@ public class EquippedCargoBay : EquippedItem
             return false;
         }
 
-        // Whole or nothing: the target must be able to take the part before it leaves the stack.
-        var part = new SimpleCommodity { Data = item.Data, Quantity = min(quantity, item.Quantity), Rotation = item.Rotation };
-        if (!target.TryFindSpace(part, out _)) return false;
-
         var oldPos = Cargo[item];
         var newItem = Remove(item, quantity);
 
         // The part removed goes across, never the stack left behind.
         if (target.TryStore(newItem)) return true;
 
-        // The target refused after all: put the part back where it came from.
+        // Whole or nothing: TryStore takes all of the part or none of it, so a refusal puts the part back where it came from.
         TryStore(newItem, oldPos);
         return false;
     }

tests/Aetheria.Shared.Tests/CargoTransferTests.cs

@@ -165,8 +165,9 @@ public sealed class CargoTransferTests : IDisposable
         var receiver = ShipWith(receiverBay);
         var stack = Commodity("Ore", ore);
         if (ore > 0) Assert.True(giver.CargoBays[0].TryStore(stack));
-        giver.Position = new float3(0, 0, 0);
-        receiver.Position = new float3(5, 0, 0);
+        // Off the origin, so a distance taken from the wrong sum or difference of positions shows.
+        giver.Position = new float3(-50, 0, 10);
+        receiver.Position = giver.Position + new float3(5, 0, 0);
         _zone.Admit(giver, piloted: false);
         _zone.Admit(receiver, piloted: false);
         return (giver, receiver, stack);
@@ -216,13 +217,13 @@ public sealed class CargoTransferTests : IDisposable
     {
         var (giver, receiver, ore) = Alongside(10);
         var range = _items.GameplaySettings.DockingDistance;
-        receiver.Position = new float3(range - 1, 0, 0);
+        receiver.Position = giver.Position + new float3(range - 1, 0, 0);
         giver.Command.Give(receiver, ore, 10);
         Steps(10);
         Assert.Equal(2, Held(receiver, ore));
         Assert.Null(giver.LastGiveEnd);
 
-        receiver.Position = new float3(range + 1, 0, 0);
+        receiver.Position = giver.Position + new float3(range + 1, 0, 0);
         Steps(10);
 
         Assert.Equal(2, Held(receiver, ore));
@@ -230,12 +231,65 @@ public sealed class CargoTransferTests : IDisposable
         Assert.Equal(GiveEnd.OutOfRange, giver.LastGiveEnd);
     }
 
+    [Fact]
+    public void AReceiverExactlyAtTheDockingDistanceIsStillAlongside()
+    {
+        var (giver, receiver, ore) = Alongside(10);
+        receiver.Position = giver.Position + new float3(0, 0, _items.GameplaySettings.DockingDistance);
+        giver.Command.Give(receiver, ore, 10);
+        Steps(10);
+        Assert.Equal(2, Held(receiver, ore));
+        Assert.Null(giver.LastGiveEnd);
+    }
+
+    [Fact]
+    public void AStepOfExactlyOneUnitMovesOneUnit()
+    {
+        var (giver, receiver, ore) = Alongside(10);
+        giver.Command.Give(receiver, ore, 10);
+        _zone.Update(1f / _items.GameplaySettings.TransferRate);
+        Assert.Equal(1, Held(receiver, ore));
+    }
+
+    [Fact]
+    public void ALongStepNeverMovesMoreThanTheQuantity()
+    {
+        var (giver, receiver, ore) = Alongside(10);
+        giver.Command.Give(receiver, ore, 3);
+        _zone.Update(5f);
+        Assert.Equal(3, Held(receiver, ore));
+        Assert.Equal(7, Held(giver, ore));
+        Assert.Equal(GiveEnd.Done, giver.LastGiveEnd);
+    }
+
+    [Fact]
+    public void AGiveOfOneMovesOne()
+    {
+        var (giver, receiver, ore) = Alongside(10);
+        giver.Command.Give(receiver, ore, 1);
+        Steps(20);
+        Assert.Equal(1, Held(receiver, ore));
+        Assert.Equal(GiveEnd.Done, giver.LastGiveEnd);
+    }
+
+    [Fact]
+    public void AGiveOfACraftedItemTheGiverDoesNotHoldEndsNothingLeft()
+    {
+        var (giver, receiver, _) = Alongside(0);
+        var gun = Mint("Gun");
+        Assert.True(receiver.CargoBays[0].TryStore(gun));
+        giver.Command.Give(receiver, gun, 1);
+        Steps(20);
+        Assert.Equal(GiveEnd.NothingLeft, giver.LastGiveEnd);
+        Assert.True(receiver.CargoBays[0].Cargo.ContainsKey(gun));
+    }
+
     [Fact]
     public void GiveRangeIsMeasuredOnTheFlatPlane()
     {
         // The plane is xz: a ship far apart in y only is still alongside.
         var (giver, receiver, ore) = Alongside(10);
-        receiver.Position = new float3(5, 1000, 0);
+        receiver.Position = giver.Position + new float3(5, 1000, 0);
         giver.Command.Give(receiver, ore, 10);
         Steps(10);
         Assert.Equal(2, Held(receiver, ore));
@@ -346,7 +400,7 @@ public sealed class CargoTransferTests : IDisposable
     {
         var (giver, receiver, ore) = Alongside(10);
         var third = ShipWith("Crate");
-        third.Position = new float3(0, 0, 5);
+        third.Position = giver.Position + new float3(0, 0, 5);
         _zone.Admit(third, piloted: false);
 
         // A give then a stop leaves nothing, and nothing ended.