Nip44Encrypt test and error return

lib/src/nip46_signer_actor.dart

@@ -83,6 +83,11 @@ class Nip46SignerActor with Handler<SignerMessage, SignerResult> {
       GetPublicKey() => _getPublicKey(),
       SignEvent(:final kind, :final tags, :final content, :final createdAt) =>
         _remoteSignEvent(kind, tags, content, createdAt),
+      // NIP-44 encrypt/decrypt is not proxied to the remote signer yet; only
+      // get_public_key and sign_event are requested at connect time.
+      Nip44Encrypt() || Nip44Decrypt() => throw UnsupportedError(
+          'NIP-44 encrypt/decrypt is not supported by Nip46SignerActor',
+        ),
     };
   }
 
@@ -118,7 +123,8 @@ class Nip46SignerActor with Handler<SignerMessage, SignerResult> {
       }
     ]));
 
-    await _request('connect', [_appPubkey, _secret ?? '', 'sign_event,get_public_key']);
+    await _request(
+        'connect', [_appPubkey, _secret ?? '', 'sign_event,get_public_key']);
     _connected = true;
   }
 
@@ -134,7 +140,12 @@ class Nip46SignerActor with Handler<SignerMessage, SignerResult> {
     int? createdAt,
   ) async {
     final ts = createdAt ?? DateTime.now().millisecondsSinceEpoch ~/ 1000;
-    final unsigned = {'kind': kind, 'content': content, 'tags': tags, 'created_at': ts};
+    final unsigned = {
+      'kind': kind,
+      'content': content,
+      'tags': tags,
+      'created_at': ts
+    };
     final result = await _request('sign_event', [jsonEncode(unsigned)]);
     return EventSigned(result);
   }
@@ -143,7 +154,12 @@ class Nip46SignerActor with Handler<SignerMessage, SignerResult> {
     final id = _randomId();
     final body = jsonEncode({'id': id, 'method': method, 'params': params});
     final encrypted = nip44Encrypt(body, _appPrivkey, _signerPubkey);
-    final eventJson = _signAppEvent(kind: 24133, tags: [['p', _signerPubkey]], content: encrypted);
+    final eventJson = _signAppEvent(
+        kind: 24133,
+        tags: [
+          ['p', _signerPubkey]
+        ],
+        content: encrypted);
 
     final completer = Completer<String>();
     _pending[id] = completer;

test/nostr_signer_actor_test.dart

@@ -104,4 +104,30 @@ void main() {
     expect(ts, greaterThanOrEqualTo(before));
     expect(ts, lessThanOrEqualTo(after + 2));
   });
+
+  test('Nip44Encrypt round-trips to self', () async {
+    final plaintext = jsonEncode({'blur_content_warnings': 'false', 'x': '1'});
+    final encrypted = await signer.handle(Nip44Encrypt(plaintext)) as Nip44Text;
+    expect(encrypted.value, isNot(equals(plaintext)));
+
+    // Payload is base64 with the NIP-44 v2 version byte (0x02) first.
+    final bytes = base64.decode(encrypted.value);
+    expect(bytes.first, equals(0x02));
+
+    final decrypted =
+        await signer.handle(Nip44Decrypt(encrypted.value)) as Nip44Text;
+    expect(decrypted.value, equals(plaintext));
+  });
+
+  test('Nip44Decrypt with a foreign key fails', () async {
+    final encrypted =
+        await signer.handle(const Nip44Encrypt('secret')) as Nip44Text;
+    final other = NostrSignerActor(
+      '0000000000000000000000000000000000000000000000000000000000000002',
+    );
+    expect(
+      () => other.handle(Nip44Decrypt(encrypted.value)),
+      throwsA(anything),
+    );
+  });
 }