auto(agent): enhance offers tests with message length validation

backend/src/__tests__/offers.test.js

@@ -99,4 +99,32 @@ test('POST /offers/accept/:offerId should return 404 for non-existent offer', as
     payload: {}
   });
   assert.strictEqual(response.statusCode, 404);
+});
+
+// Additional test for validation of message length
+test('POST /offers/:requestId should return 400 for message exceeding max length', async () => {
+  const longMessage = 'a'.repeat(2001); // 2001 characters
+  const response = await app.inject({
+    method: 'POST',
+    url: '/offers/1',
+    payload: {
+      amountChf: 50,
+      message: longMessage
+    }
+  });
+  assert.strictEqual(response.statusCode, 400);
+});
+
+// Additional test for validation of negotiation message length
+test('POST /offers/negotiation/:offerId should return 400 for message exceeding max length', async () => {
+  const longMessage = 'a'.repeat(2001); // 2001 characters
+  const response = await app.inject({
+    method: 'POST',
+    url: '/offers/negotiation/1',
+    payload: {
+      amountChf: 60,
+      message: longMessage
+    }
+  });
+  assert.strictEqual(response.statusCode, 400);
 });