fix(tests): address nits found by arkana

Author: d4rp4t

NArk.Tests.End2End/BatchSessionTests.cs

@@ -263,6 +263,9 @@ await spendingService.Spend(walletDetails.walletIdentifier,
             $"Offchain tx with {numInputs} input VTXOs must produce exactly {numInputs} checkpoint transactions");
     }
 
+    // Decorator that records the checkpoint count passed to SubmitTx.
+    // Must implement every IClientTransport method — if the interface gains a new member
+    // this breaks at compile time, which is intentional (fail loudly, don't silently skip).
     private sealed class CheckpointSpyTransport(IClientTransport inner) : IClientTransport
     {
         public int LastSubmitCheckpointCount { get; private set; }
@@ -319,4 +322,4 @@ public Task<IReadOnlyList<string>> GetVirtualTxsAsync(IReadOnlyList<string> txid
         public Task<IReadOnlyList<VtxoTreeNode>> GetVtxoTreeAsync(OutPoint batchOutpoint, CancellationToken cancellationToken = default)
             => inner.GetVtxoTreeAsync(batchOutpoint, cancellationToken);
     }
-}
+}

NArk.Tests.End2End/NoteTests.cs

@@ -242,4 +242,4 @@ await Task.WhenAll(
 
         await Task.WhenAll(host1.StopAsync(), host2.StopAsync());
     }
-}
+}

NArk.Tests.End2End/OnchainTests.cs

@@ -199,4 +199,4 @@ await intentGenService.GenerateManualIntent(walletId,
         Assert.That(cancelled.CancellationReason, Is.Not.Null.And.Not.Empty,
             "Cancellation reason should contain arkd's rejection message");
     }
-}
+}

NArk.Tests.End2End/SubdustRejectionTests.cs

@@ -73,11 +73,12 @@ await aliceSpending.Spend(alice.walletIdentifier,
             bobContractService, alice.clientTransport, new DefaultCoinSelector(),
             alice.safetyService, TestStorage.CreateIntentStorage());
 
-        // Assert.CatchAsync accepts any exception subtype (unlike Assert.ThrowsAsync which requires exact match)
         var ex = Assert.CatchAsync(
             () => bobSpending.Spend(bobWalletId,
                 [new ArkTxOut(ArkTxOutType.Vtxo, Money.Satoshis(100), carolContract.GetArkAddress())]));
         Assert.That(ex, Is.Not.Null, "Spending a sub-dust VTXO must be rejected");
+        Assert.That(ex!.Message, Does.Contain("dust").IgnoreCase,
+            "Exception must originate from the dust threshold check, not an unrelated error");
     }
 
     /// <summary>

NArk.Tests/BoltzSwapProvider404SafetyNetTests.cs

@@ -172,7 +172,7 @@ public async Task SuccessfulPollResetsCounter_SubsequentThresholdIsIndependent()
 
         // Interleaved handler: first (Threshold-1) requests → 404, then one success, then 404s again
         var callCount = 0;
-        var handler = new DelegatingHandler(req =>
+        var handler = new FakeHandler(req =>
         {
             callCount++;
             if (callCount < Threshold || callCount == Threshold)
@@ -223,7 +223,7 @@ protected override Task<HttpResponseMessage> SendAsync(
             => Task.FromResult(NotFoundResponse(swapId));
     }
 
-    private sealed class DelegatingHandler(
+    private sealed class FakeHandler(
         Func<HttpRequestMessage, HttpResponseMessage> responder) : HttpMessageHandler
     {
         protected override Task<HttpResponseMessage> SendAsync(