From 280312a6e24ff694d3757e62453eb6aff4d69465 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Adrien=20Coye=20de=20Brune=CC=81lis?=
 <adrien.coye@infomaniak.com>
Date: Fri, 26 Jan 2024 16:27:23 +0100
Subject: [PATCH] fix: Priority inversion could happend with
 TolerantDispatchGroup. test: Unit testing TolerantDispatchGroup QoS

---
 .../Asynchronous/TolerantDispatchGroup.swift  |  6 ++--
 .../UTTolerantDispatchGroup.swift             | 32 ++++++++++++++++++-
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/Sources/InfomaniakCore/Asynchronous/TolerantDispatchGroup.swift b/Sources/InfomaniakCore/Asynchronous/TolerantDispatchGroup.swift
index d5b4697..a1c3b31 100644
--- a/Sources/InfomaniakCore/Asynchronous/TolerantDispatchGroup.swift
+++ b/Sources/InfomaniakCore/Asynchronous/TolerantDispatchGroup.swift
@@ -20,12 +20,12 @@ import CocoaLumberjackSwift
 import Foundation
 
 public final class TolerantDispatchGroup {
-    private let syncQueue = DispatchQueue(label: "com.infomaniak.TolerantDispatchGroup")
+    let syncQueue: DispatchQueue
     private let dispatchGroup = DispatchGroup()
     private var callBalancer = 0
 
-    public init() {
-        // Meta: Keep Sonar Cloud happy
+    public init(qos: DispatchQoS = .default) {
+        syncQueue = DispatchQueue(label: "com.infomaniak.TolerantDispatchGroup", qos: qos)
     }
     
     public func enter() {
diff --git a/Tests/InfomaniakCoreTests/UTTolerantDispatchGroup.swift b/Tests/InfomaniakCoreTests/UTTolerantDispatchGroup.swift
index 134913e..72dc02e 100644
--- a/Tests/InfomaniakCoreTests/UTTolerantDispatchGroup.swift
+++ b/Tests/InfomaniakCoreTests/UTTolerantDispatchGroup.swift
@@ -16,9 +16,15 @@
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-import InfomaniakCore
+@testable import InfomaniakCore
 import XCTest
 
+extension DispatchQoS: CaseIterable {
+    public static var allCases: [DispatchQoS] {
+        [.background, .utility, .default, .userInitiated, .userInteractive, .unspecified]
+    }
+}
+
 final class UTTolerantDispatchGroup: XCTestCase {
     func testCanInit() {
         // WHEN
@@ -27,4 +33,28 @@ final class UTTolerantDispatchGroup: XCTestCase {
         // THEN
         XCTAssertNotNil(dispatchGroup)
     }
+
+    func testPriorityDefault() {
+        // WHEN
+        let dispatchGroup = TolerantDispatchGroup()
+
+        // THEN
+        XCTAssertNotNil(dispatchGroup)
+        XCTAssertEqual(dispatchGroup.syncQueue.qos, DispatchQoS.default, "default constructor should have default priority")
+    }
+
+    func testPriorityAnyIsSet() {
+        // GIVEN
+        guard let expectedQoS = DispatchQoS.allCases.randomElement() else {
+            XCTFail("unexpected")
+            return
+        }
+
+        // WHEN
+        let dispatchGroup = TolerantDispatchGroup(qos: expectedQoS)
+
+        // THEN
+        XCTAssertNotNil(dispatchGroup)
+        XCTAssertEqual(dispatchGroup.syncQueue.qos, expectedQoS, "QoS should match")
+    }
 }