diff --git a/backend/package.json b/backend/package.json
index bf099be..c338c41 100644
--- a/backend/package.json
+++ b/backend/package.json
@@ -20,9 +20,10 @@
     "test:users": "tsx src/modules/users/iface-type.test.ts && tsx src/modules/users/bindings.test.ts",
     "test:pg": "tsx src/db/sql-bind.test.ts && tsx src/db/sqlite-json.test.ts && tsx src/db/traffic-flags.test.ts && tsx src/db/pg-schema.test.ts && tsx src/services/config-revisions.test.ts",
     "test:config-sync": "tsx src/services/config-apply-plan.test.ts && tsx src/services/entity-snapshots.test.ts",
+    "test:ros-file": "tsx src/services/ros-file-contents.test.ts",
     "test:backups": "tsx src/services/s3-backup-client.test.ts",
     "test:live-maps": "tsx src/services/ospf-route-parse.test.ts && tsx src/services/vxlan-live.test.ts && tsx src/services/containers-live.test.ts",
-    "test": "npm run test:alert-engine && npm run test:auth && npm run test:wireguard && npm run test:traffic-rate && npm run test:traffic-flow && npm run test:users && npm run test:pg && npm run test:backups && npm run test:live-maps && npm run test:config-sync",
+    "test": "npm run test:alert-engine && npm run test:auth && npm run test:wireguard && npm run test:traffic-rate && npm run test:traffic-flow && npm run test:users && npm run test:pg && npm run test:backups && npm run test:live-maps && npm run test:config-sync && npm run test:ros-file",
     "test:geoip": "tsx src/services/traffic-flow-geoip.test.ts"
   },
   "dependencies": {
diff --git a/backend/src/services/ros-file-contents.test.ts b/backend/src/services/ros-file-contents.test.ts
new file mode 100644
index 0000000..6376d26
--- /dev/null
+++ b/backend/src/services/ros-file-contents.test.ts
@@ -0,0 +1,66 @@
+import assert from "node:assert/strict"
+import { extractRosContentsField } from "./mikrotik.js"
+
+/**
+ * Собирает ответ RouterOS на `/file/get` (.proplist=contents) в том виде, в каком его
+ * отдаёт устройство: single-byte строка, экранируются только кавычка и обратный слэш.
+ */
+function rosFileGetResponse(contents: Buffer): Buffer {
+  const escaped: number[] = []
+  for (const byte of contents) {
+    if (byte === 0x22 || byte === 0x5c) escaped.push(0x5c, byte)
+    else escaped.push(byte)
+  }
+  return Buffer.concat([
+    Buffer.from('[{".id":"*A","contents":"', "latin1"),
+    Buffer.from(escaped),
+    Buffer.from('"}]', "latin1"),
+  ])
+}
+
+{
+  // ASCII-содержимое
+  const content = Buffer.from("hello p12", "latin1")
+  assert.deepEqual(extractRosContentsField(rosFileGetResponse(content)), content)
+}
+
+{
+  // Экранированные кавычки и обратный слэш
+  const content = Buffer.from('a"b\\c"d', "latin1")
+  assert.deepEqual(extractRosContentsField(rosFileGetResponse(content)), content)
+}
+
+{
+  // Пустой файл
+  assert.equal(extractRosContentsField(rosFileGetResponse(Buffer.alloc(0))).length, 0)
+}
+
+{
+  // Управляющие escape-последовательности
+  const raw = Buffer.from('{"contents":"a\\nb\\tc\\u0041"}', "latin1")
+  assert.deepEqual(extractRosContentsField(raw), Buffer.from("a\nb\tcA", "latin1"))
+}
+
+{
+  // contents не первый ключ в объекте
+  const raw = Buffer.from('{".id":"*B","name":"x.p12","contents":"DATA"}', "latin1")
+  assert.deepEqual(extractRosContentsField(raw), Buffer.from("DATA", "latin1"))
+}
+
+{
+  // Все 256 байт: single-byte кодировка не должна терять значения 0x80–0xFF и NUL
+  const content = Buffer.from(Array.from({ length: 256 }, (_, i) => i))
+  const decoded = extractRosContentsField(rosFileGetResponse(content))
+  assert.equal(decoded.length, 256)
+  assert.deepEqual(decoded, content)
+}
+
+{
+  // Нет поля contents — понятная ошибка
+  assert.throws(
+    () => extractRosContentsField(Buffer.from('{".id":"*A"}', "latin1")),
+    /не содержит поле contents/,
+  )
+}
+
+console.log("ros-file-contents.test.ts: ok")