Fix macOS CI tests

Tests/LibraryRefreshViewModelTest.swift

@@ -21,12 +21,14 @@ import Combine
 @testable import Kiwix
 
 private class HTTPTestingURLProtocol: URLProtocol {
+    @MainActor
     static var handler: ((URLProtocol) -> Void)?
 
     override class func canInit(with request: URLRequest) -> Bool { true }
     override class func canonicalRequest(for request: URLRequest) -> URLRequest { request }
     override func stopLoading() { }
 
+    @MainActor
     override func startLoading() {
         if let handler = HTTPTestingURLProtocol.handler {
             handler(self)
@@ -37,9 +39,10 @@ private class HTTPTestingURLProtocol: URLProtocol {
 }
 
 final class LibraryRefreshViewModelTest: XCTestCase {
-    private var urlSession: URLSession?
+    private var urlSession: URLSession!
     private var cancellables = Set<AnyCancellable>()
 
+    @MainActor
     override func setUpWithError() throws {
         let config = URLSessionConfiguration.ephemeral
         config.protocolClasses = [HTTPTestingURLProtocol.self]
@@ -57,6 +60,7 @@ final class LibraryRefreshViewModelTest: XCTestCase {
         }
     }
 
+    @MainActor
     override func tearDownWithError() throws {
         HTTPTestingURLProtocol.handler = nil
     }

ViewModel/LibraryViewModel.swift

@@ -103,12 +103,12 @@ final class LibraryViewModel: ObservableObject {
 
     @MainActor
     init(
-        urlSession: URLSession? = nil,
+        urlSession: URLSession = URLSession.shared,
         processFactory: @MainActor () -> LibraryProcess = { .shared },
         defaults: Defaulting = UDefaults(),
         categories: CategoriesProtocol = CategoriesToLanguages(withDefaults: UDefaults())
     ) {
-        self.urlSession = urlSession ?? URLSession.shared
+        self.urlSession = urlSession
         self.process = processFactory()
         self.defaults = defaults
         self.categories = categories

Views/BuildingBlocks/ZimFileCell.swift

@@ -17,7 +17,7 @@ import CoreData
 import SwiftUI
 
 struct ZimFileCell: View {
-    @ObservedObject var zimFile: ZimFile
+    @MainActor @ObservedObject var zimFile: ZimFile
     @State private var isHovering: Bool = false
     let isLoading: Bool
     let isSelected: Bool