test: verify sentinel + decode-error conformance vectors

Harness + CI now check sentinel.jsonl and errors.jsonl at vectors v1.1.0.

Author: ajsb85

.github/workflows/ci.yml

@@ -68,6 +68,10 @@ jobs:
       - 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
+        run: |
+          base=https://raw.githubusercontent.com/firechip/cobs-conformance/v1.1.0/vectors
+          curl -sSfL -o vectors.jsonl "$base/vectors.jsonl"
+          curl -sSfL -o sentinel.jsonl "$base/sentinel.jsonl"
+          curl -sSfL -o errors.jsonl "$base/errors.jsonl"
       - name: Check conformance
-        run: dart run tool/conformance.dart vectors.jsonl
+        run: dart run tool/conformance.dart vectors.jsonl sentinel.jsonl errors.jsonl

tool/conformance.dart

@@ -1,7 +1,7 @@
 // Verifies this package against the shared conformance vectors from
 // https://github.com/firechip/cobs-conformance
 //
-// Usage: dart run tool/conformance.dart <vectors.jsonl>
+// Usage: dart run tool/conformance.dart <vectors.jsonl> [sentinel.jsonl] [errors.jsonl]
 import 'dart:convert';
 import 'dart:io';
 import 'dart:typed_data';
@@ -21,6 +21,8 @@ String _toHex(List<int> b) =>
 
 void main(List<String> args) {
   final path = args.isNotEmpty ? args[0] : 'vectors.jsonl';
+  final sentinelPath = args.length > 1 ? args[1] : null;
+  final errorsPath = args.length > 2 ? args[2] : null;
   var checked = 0;
   var failures = 0;
 
@@ -48,6 +50,73 @@ void main(List<String> args) {
     checked++;
   }
 
+  // Configurable-sentinel vectors: encode/decode round-trips for an arbitrary
+  // sentinel byte, plus the invariant that the sentinel never appears in output.
+  if (sentinelPath != null) {
+    for (final line in File(sentinelPath).readAsLinesSync()) {
+      if (line.trim().isEmpty) continue;
+      final v = json.decode(line) as Map<String, dynamic>;
+      final decodedHex = v['decoded'] as String;
+      final sentinelHex = v['sentinel'] as String;
+      final cobsHex = v['cobs'] as String;
+      final cobsrHex = v['cobsr'] as String;
+      final decoded = _hex(decodedHex);
+      final sentinel = _hex(sentinelHex)[0];
+
+      check(_toHex(cobsEncodeWithSentinel(decoded, sentinel)) == cobsHex,
+          'sentinel $sentinelHex cobs encode $decodedHex');
+      check(_toHex(cobsrEncodeWithSentinel(decoded, sentinel)) == cobsrHex,
+          'sentinel $sentinelHex cobsr encode $decodedHex');
+      check(
+          _toHex(cobsDecodeWithSentinel(_hex(cobsHex), sentinel)) == decodedHex,
+          'sentinel $sentinelHex cobs decode $cobsHex');
+      check(
+          _toHex(cobsrDecodeWithSentinel(_hex(cobsrHex), sentinel)) ==
+              decodedHex,
+          'sentinel $sentinelHex cobsr decode $cobsrHex');
+      check(!_hex(cobsHex).contains(sentinel),
+          'sentinel $sentinelHex present in cobs $cobsHex');
+      check(!_hex(cobsrHex).contains(sentinel),
+          'sentinel $sentinelHex present in cobsr $cobsrHex');
+      checked++;
+    }
+  }
+
+  // Error/decode-outcome vectors: decoding `encoded` must yield the expected
+  // hex, or throw a CobsDecodeException when the expected value is JSON null.
+  if (errorsPath != null) {
+    void checkOutcome(String label, Uint8List input, Object? expected,
+        Uint8List Function(List<int>) decode, String encodedHex) {
+      if (expected == null) {
+        var threw = false;
+        try {
+          decode(input);
+        } on CobsDecodeException {
+          threw = true;
+        }
+        check(threw, '$label decode should fail $encodedHex');
+      } else {
+        try {
+          check(_toHex(decode(input)) == expected,
+              '$label decode $encodedHex -> $expected');
+        } on CobsDecodeException {
+          check(false, '$label decode unexpectedly failed $encodedHex');
+        }
+      }
+    }
+
+    for (final line in File(errorsPath).readAsLinesSync()) {
+      if (line.trim().isEmpty) continue;
+      final v = json.decode(line) as Map<String, dynamic>;
+      final encodedHex = v['encoded'] as String;
+      final encoded = _hex(encodedHex);
+
+      checkOutcome('cobs', encoded, v['cobs'], cobsDecode, encodedHex);
+      checkOutcome('cobsr', encoded, v['cobsr'], cobsrDecode, encodedHex);
+      checked++;
+    }
+  }
+
   stdout.writeln('Conformance: checked $checked vectors, $failures failures.');
   if (checked == 0) {
     stderr.writeln('ERROR: no vectors found in $path');