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

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

@@ -417,16 +417,50 @@ private static List<TransactionTest> ConvertTransactionTests(Dictionary<string,
             return tests;
         }
 
+        private const string NeitherShapeMessage = "Fixture matches neither the standard nor the trimmed blockchain test shape.";
+
+        /// <remarks>Only deserialization falls back between shapes, so a conversion failure surfaces as itself.</remarks>
         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 standardShapeException)
+            {
+                try
+                {
+                    tests = CoerceFromHalf(_serializer.Deserialize<Dictionary<string, HalfBlockchainTestJson>>(json));
+                }
+                catch (Exception trimmedShapeException)
+                {
+                    throw new AggregateException(NeitherShapeMessage, standardShapeException, trimmedShapeException);
+                }
+            }
+            return ConvertToBlockchainTests(tests);
         }
 
+        /// <remarks>Only deserialization falls back between shapes, so a conversion failure surfaces as itself.</remarks>
         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 standardShapeException)
+            {
+                try
+                {
+                    tests = CoerceFromHalf(_serializer.Deserialize<Dictionary<string, HalfBlockchainTestJson>>(json));
+                }
+                catch (Exception trimmedShapeException)
+                {
+                    throw new AggregateException(NeitherShapeMessage, standardShapeException, trimmedShapeException);
+                }
+            }
+            return ConvertToBlockchainTests(tests);
         }
 
         // Some BAL fixtures use the trimmed HalfBlockchainTestJson shape; coerce on demand.

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

@@ -0,0 +1,30 @@
+// SPDX-FileCopyrightText: 2026 Demerzel Solutions Limited
+// SPDX-License-Identifier: LGPL-3.0-only
+
+using System;
+using Nethermind.Core.Specs;
+using Nethermind.Specs.Forks;
+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, Is.SameAs(Bogota.Instance));
+    }
+
+    [TestCase("NotAFork", "NotAFork")]
+    [TestCase("Merge+9999", "Paris+9999")]
+    public void Parse_names_the_offending_fork_when_unmapped(string specName, string resolvedSpecName)
+    {
+        NotSupportedException e = Assert.Throws<NotSupportedException>(() => SpecNameParser.Parse(specName))!;
+
+        Assert.That(e.Message, Does.Contain(specName));
+        Assert.That(e.Message, Does.Contain(resolvedSpecName));
+    }
+}

src/Nethermind/Nethermind.Specs/SpecNameParser.cs

@@ -62,7 +62,10 @@ private static IReleaseSpec ParseUncached(string specName)
                 "BPO4" => BPO4.Instance,
                 "BPO5" => BPO5.Instance,
                 "Amsterdam" => Amsterdam.Instance,
-                _ => throw new NotSupportedException()
+                "Bogota" => Bogota.Instance,
+                _ => throw new NotSupportedException(specName == unambiguousSpecName
+                    ? $"Unknown fork name '{specName}'"
+                    : $"Unknown fork name '{specName}' (resolved to '{unambiguousSpecName}')")
             };
         }
     }