test: load the frame transaction fixtures by mapping their fork name

src/Nethermind/Ethereum.Test.Base/JsonToEthereumTest.cs

@@ -417,16 +417,22 @@ private static List<TransactionTest> ConvertTransactionTests(Dictionary<string,
             return tests;
         }
 
+        // The shape fallback deliberately wraps deserialization only: letting it span conversion
+        // made an unmapped fork name resurface as an unrelated error against the trimmed shape.
         public static IEnumerable<BlockchainTest> ConvertToBlockchainTests(string json)
         {
-            try { return ConvertToBlockchainTests(_serializer.Deserialize<Dictionary<string, BlockchainTestJson>>(json)); }
-            catch (Exception) { return ConvertToBlockchainTests(CoerceFromHalf(_serializer.Deserialize<Dictionary<string, HalfBlockchainTestJson>>(json))); }
+            Dictionary<string, BlockchainTestJson> tests;
+            try { tests = _serializer.Deserialize<Dictionary<string, BlockchainTestJson>>(json); }
+            catch (Exception) { tests = CoerceFromHalf(_serializer.Deserialize<Dictionary<string, HalfBlockchainTestJson>>(json)); }
+            return ConvertToBlockchainTests(tests);
         }
 
         public static IEnumerable<BlockchainTest> ConvertToBlockchainTests(ReadOnlySpan<byte> json)
         {
-            try { return ConvertToBlockchainTests(_serializer.Deserialize<Dictionary<string, BlockchainTestJson>>(json)); }
-            catch (Exception) { return ConvertToBlockchainTests(CoerceFromHalf(_serializer.Deserialize<Dictionary<string, HalfBlockchainTestJson>>(json))); }
+            Dictionary<string, BlockchainTestJson> tests;
+            try { tests = _serializer.Deserialize<Dictionary<string, BlockchainTestJson>>(json); }
+            catch (Exception) { tests = CoerceFromHalf(_serializer.Deserialize<Dictionary<string, HalfBlockchainTestJson>>(json)); }
+            return ConvertToBlockchainTests(tests);
         }
 
         // Some BAL fixtures use the trimmed HalfBlockchainTestJson shape; coerce on demand.

src/Nethermind/Nethermind.Specs.Test/SpecNameParserTests.cs

@@ -0,0 +1,27 @@
+// SPDX-FileCopyrightText: 2026 Demerzel Solutions Limited
+// SPDX-License-Identifier: LGPL-3.0-only
+
+using System;
+using Nethermind.Core.Specs;
+using NUnit.Framework;
+
+namespace Nethermind.Specs.Test;
+
+public class SpecNameParserTests
+{
+    [Test]
+    public void Parse_maps_Bogota_to_the_frame_transactions_fork()
+    {
+        IReleaseSpec spec = SpecNameParser.Parse("Bogota");
+
+        Assert.That(spec.IsEip8141Enabled, Is.True);
+    }
+
+    [Test]
+    public void Parse_names_the_offending_fork_when_unmapped()
+    {
+        NotSupportedException e = Assert.Throws<NotSupportedException>(() => SpecNameParser.Parse("NotAFork"));
+
+        Assert.That(e.Message, Does.Contain("NotAFork"));
+    }
+}

src/Nethermind/Nethermind.Specs/SpecNameParser.cs

@@ -62,7 +62,8 @@ private static IReleaseSpec ParseUncached(string specName)
                 "BPO4" => BPO4.Instance,
                 "BPO5" => BPO5.Instance,
                 "Amsterdam" => Amsterdam.Instance,
-                _ => throw new NotSupportedException()
+                "Bogota" => Bogota.Instance,
+                _ => throw new NotSupportedException($"Unknown fork name '{specName}'")
             };
         }
     }