feat: Reimplement the OMEMOMessage protobuf schema

test/protobuf.dart

@@ -0,0 +1,110 @@
+import 'package:omemo_dart/protobuf/schema.pb.dart';
+import 'package:omemo_dart/src/protobuf/omemo_message.dart';
+import 'package:omemo_dart/src/protobuf/protobuf.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('Base 128 Varints', () {
+    test('Test simple parsing of Varints', () {
+      expect(
+        decodeVarint(<int>[1], 0).n,
+        1,
+      );
+      expect(
+        decodeVarint(<int>[1], 0).length,
+        1,
+      );
+      expect(
+        decodeVarint(<int>[0x96, 0x01, 0x00], 0).n,
+        150,
+      );
+      expect(
+        decodeVarint(<int>[0x96, 0x01, 0x00], 0).length,
+        2,
+      );
+      expect(
+        decodeVarint(<int>[172, 2, 0x8], 0).n,
+        300,
+      );
+      expect(
+        decodeVarint(<int>[172, 2, 0x8], 0).length,
+        2,
+      );
+    });
+
+    test('Test encoding Varints', () {
+      expect(
+        encodeVarint(1),
+        <int>[1],
+      );
+      expect(
+        encodeVarint(150),
+        <int>[0x96, 0x01],
+      );
+      expect(
+        encodeVarint(300),
+        <int>[172, 2],
+      );
+    });
+  });
+
+  group('OMEMOMessage', () {
+    test('Decode a OMEMOMessage', () {
+      final pbMessage = OMEMOMessage()
+        ..n = 1
+        ..pn = 5
+        ..dhPub = <int>[1, 2, 3]
+        ..ciphertext = <int>[4, 5, 6];
+      final serial = pbMessage.writeToBuffer();
+      final msg = OmemoMessage.fromBuffer(serial);
+
+      expect(msg.n, 1);
+      expect(msg.pn, 5);
+      expect(msg.dhPub, <int>[1, 2, 3]);
+      expect(msg.ciphertext, <int>[4, 5, 6]);
+    });
+    test('Decode a OMEMOMessage without ciphertext', () {
+      final pbMessage = OMEMOMessage()
+        ..n = 1
+        ..pn = 5
+        ..dhPub = <int>[1, 2, 3];
+      final serial = pbMessage.writeToBuffer();
+      final msg = OmemoMessage.fromBuffer(serial);
+      
+      expect(msg.n, 1);
+      expect(msg.pn, 5);
+      expect(msg.dhPub, <int>[1, 2, 3]);
+      expect(msg.ciphertext, null);
+    });
+    test('Encode a OMEMOMessage', () {
+      const m = OmemoMessage(
+        1,
+        5,
+        <int>[1, 2, 3],
+        <int>[4, 5, 6],
+      );
+      final serial = m.writeToBuffer();
+      final msg = OMEMOMessage.fromBuffer(serial);
+      
+      expect(msg.n, 1);
+      expect(msg.pn, 5);
+      expect(msg.dhPub, <int>[1, 2, 3]);
+      expect(msg.ciphertext, <int>[4, 5, 6]);
+    });
+    test('Encode a OMEMOMessage without ciphertext', () {
+      const m = OmemoMessage(
+        1,
+        5,
+        <int>[1, 2, 3],
+        null,
+      );
+      final serial = m.writeToBuffer();
+      final msg = OMEMOMessage.fromBuffer(serial);
+
+      expect(msg.n, 1);
+      expect(msg.pn, 5);
+      expect(msg.dhPub, <int>[1, 2, 3]);
+      expect(msg.ciphertext, <int>[]);
+    });
+  });
+}