verifyNostrEvent helper

test/nostr_event_test.dart

@@ -0,0 +1,53 @@
+import 'dart:convert';
+
+import 'package:swarm/swarm.dart';
+import 'package:test/test.dart';
+
+void main() {
+  // Produces a genuinely-signed event so verifyNostrEvent has a real signature
+  // to check (signed with the throwaway key below).
+  const privKey =
+      '0000000000000000000000000000000000000000000000000000000000000001';
+
+  Future<Map<String, dynamic>> signedEvent() async {
+    final signer = NostrSignerActor(privKey);
+    final result =
+        await signer.handle(
+              const SignEvent(kind: 1985, content: '', tags: [
+                ['L', 'app.xfay.moderation'],
+                ['l', 'hide', 'app.xfay.moderation'],
+                ['e', 'imageeventid'],
+              ]),
+            )
+            as EventSigned;
+    return jsonDecode(result.event) as Map<String, dynamic>;
+  }
+
+  test('accepts a genuinely signed event', () async {
+    expect(verifyNostrEvent(await signedEvent()), isTrue);
+  });
+
+  test('rejects a tampered content', () async {
+    final event = await signedEvent();
+    event['content'] = 'tampered';
+    expect(verifyNostrEvent(event), isFalse);
+  });
+
+  test('rejects a tampered id', () async {
+    final event = await signedEvent();
+    event['id'] = '${event['id']}'.replaceRange(0, 1, '0');
+    expect(verifyNostrEvent(event), isFalse);
+  });
+
+  test('rejects a forged author (pubkey swapped)', () async {
+    final event = await signedEvent();
+    event['pubkey'] =
+        '0000000000000000000000000000000000000000000000000000000000000002';
+    expect(verifyNostrEvent(event), isFalse);
+  });
+
+  test('returns false for a malformed map instead of throwing', () {
+    expect(verifyNostrEvent(const {}), isFalse);
+    expect(verifyNostrEvent(const {'kind': 1}), isFalse);
+  });
+}