ci: verify against shared cobs-conformance vectors

Adds tool/conformance.dart which checks encode/decode for both COBS and COBS/R against the canonical vectors at firechip/cobs-conformance, and a CI job that downloads the pinned v1.0.0 vectors and runs it. tool/ is excluded from the published package via .pubignore.

Signed-off-by: Alexander Salas Bastidas <ajsb85@firechip.dev>

Author: ajsb85

.github/workflows/ci.yml

@@ -58,3 +58,16 @@ jobs:
         run: |
           dart pub global activate pana
           dart pub global run pana --no-warning --exit-code-threshold 20 .
+
+  conformance:
+    name: Conformance vectors
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+      - uses: dart-lang/setup-dart@v1
+      - name: Install dependencies
+        run: dart pub get
+      - name: Download shared conformance vectors
+        run: curl -sSfL -o vectors.jsonl https://raw.githubusercontent.com/firechip/cobs-conformance/v1.0.0/vectors/vectors.jsonl
+      - name: Check conformance
+        run: dart run tool/conformance.dart vectors.jsonl

.pubignore

@@ -0,0 +1,2 @@
+# Dev-only conformance tooling; not part of the published package.
+tool/

tool/conformance.dart

@@ -0,0 +1,56 @@
+// Verifies this package against the shared conformance vectors from
+// https://github.com/firechip/cobs-conformance
+//
+// Usage: dart run tool/conformance.dart <vectors.jsonl>
+import 'dart:convert';
+import 'dart:io';
+import 'dart:typed_data';
+
+import 'package:cobs_codec/cobs_codec.dart';
+
+Uint8List _hex(String s) {
+  final out = Uint8List(s.length ~/ 2);
+  for (var i = 0; i < out.length; i++) {
+    out[i] = int.parse(s.substring(i * 2, i * 2 + 2), radix: 16);
+  }
+  return out;
+}
+
+String _toHex(List<int> b) =>
+    b.map((x) => x.toRadixString(16).padLeft(2, '0')).join();
+
+void main(List<String> args) {
+  final path = args.isNotEmpty ? args[0] : 'vectors.jsonl';
+  var checked = 0;
+  var failures = 0;
+
+  void check(bool ok, String what) {
+    if (!ok) {
+      failures++;
+      if (failures <= 10) stderr.writeln('MISMATCH: $what');
+    }
+  }
+
+  for (final line in File(path).readAsLinesSync()) {
+    if (line.trim().isEmpty) continue;
+    final v = json.decode(line) as Map<String, dynamic>;
+    final decodedHex = v['decoded'] as String;
+    final cobsHex = v['cobs'] as String;
+    final cobsrHex = v['cobsr'] as String;
+    final decoded = _hex(decodedHex);
+
+    check(_toHex(cobsEncode(decoded)) == cobsHex, 'cobs encode $decodedHex');
+    check(_toHex(cobsrEncode(decoded)) == cobsrHex, 'cobsr encode $decodedHex');
+    check(_toHex(cobsDecode(_hex(cobsHex))) == decodedHex, 'cobs decode $cobsHex');
+    check(_toHex(cobsrDecode(_hex(cobsrHex))) == decodedHex,
+        'cobsr decode $cobsrHex');
+    checked++;
+  }
+
+  stdout.writeln('Conformance: checked $checked vectors, $failures failures.');
+  if (checked == 0) {
+    stderr.writeln('ERROR: no vectors found in $path');
+    exit(1);
+  }
+  if (failures > 0) exit(1);
+}