Refactor

Tests/XXMessengerClientTests/TestHelpers/TestDoubles.swift

@@ -23,3 +23,16 @@ extension BackupParams {
     username: "stub-username"
   )
 }
+
+extension ReceivedFile {
+  static func stub(_ id: Int) -> ReceivedFile {
+    ReceivedFile(
+      transferId: "transfer-id-\(id)".data(using: .utf8)!,
+      senderId: "sender-id-\(id)".data(using: .utf8)!,
+      preview: "preview-\(id)".data(using: .utf8)!,
+      name: "name-\(id)",
+      type: "type-\(id)",
+      size: id
+    )
+  }
+}

Tests/XXMessengerClientTests/Utils/ReceiveFileCallbacksRegistryTests.swift

@@ -42,16 +42,3 @@ final class ReceiveFileCallbacksRegistryTests: XCTestCase {
     XCTAssertNoDifference(secondCallbackDidHandle, [firstResult, secondResult])
   }
 }
-
-private extension ReceivedFile {
-  static func stub(_ id: Int) -> ReceivedFile {
-    ReceivedFile(
-      transferId: "transfer-id-\(id)".data(using: .utf8)!,
-      senderId: "sender-id-\(id)".data(using: .utf8)!,
-      preview: "preview-\(id)".data(using: .utf8)!,
-      name: "name-\(id)",
-      type: "type-\(id)",
-      size: id
-    )
-  }
-}