fix(tests): prevent integration tests from overwriting production config

Tests operated on RouteManager.shared which writes to the real
config.json. Added RouteManagerTestCase base class that snapshots
and restores the config file around each test class.

Author: GeiserX

Tests/VPNBypassTests/RouteManagerIntegrationTests.swift

@@ -2,14 +2,42 @@ import XCTest
 @testable import VPNBypassCore
 import Foundation
 
+// Base class that snapshots and restores the real config FILE around each test,
+// preventing tests from corrupting the user's production config.json.
+@MainActor
+class RouteManagerTestCase: XCTestCase {
+
+    var rm: RouteManager { RouteManager.shared }
+
+    private static let configDir: URL = {
+        let appSupport = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask).first!
+        return appSupport.appendingPathComponent("VPNBypass", isDirectory: true)
+    }()
+    private static let configURL = configDir.appendingPathComponent("config.json")
+    private static let testBackupURL = configDir.appendingPathComponent("config.json.test-snapshot")
+
+    override func setUp() {
+        super.setUp()
+        try? FileManager.default.copyItem(at: Self.configURL, to: Self.testBackupURL)
+    }
+
+    override func tearDown() {
+        let fm = FileManager.default
+        if fm.fileExists(atPath: Self.testBackupURL.path) {
+            try? fm.removeItem(at: Self.configURL)
+            try? fm.moveItem(at: Self.testBackupURL, to: Self.configURL)
+            rm.loadConfig()
+        }
+        super.tearDown()
+    }
+}
+
 // Tests that exercise RouteManager public methods which modify config state.
 // Since isVPNConnected is false in tests, route application branches are skipped,
 // but config mutations, logging, and validation logic all execute.
 
 @MainActor
-final class AddDomainTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class AddDomainTests: RouteManagerTestCase {
 
     override func setUp() {
         super.setUp()
@@ -53,9 +81,7 @@ final class AddDomainTests: XCTestCase {
 }
 
 @MainActor
-final class RemoveDomainTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class RemoveDomainTests: RouteManagerTestCase {
 
     override func setUp() {
         super.setUp()
@@ -69,16 +95,13 @@ final class RemoveDomainTests: XCTestCase {
             return
         }
         rm.removeDomain(entry)
-        // removeDomain dispatches an async Task; give it time to complete
         try await Task.sleep(nanoseconds: 200_000_000)
         XCTAssertFalse(rm.config.domains.contains(where: { $0.domain == "to-remove.com" }))
     }
 }
 
 @MainActor
-final class ToggleDomainTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class ToggleDomainTests: RouteManagerTestCase {
 
     override func setUp() {
         super.setUp()
@@ -111,9 +134,7 @@ final class ToggleDomainTests: XCTestCase {
 }
 
 @MainActor
-final class SetAllDomainsEnabledTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class SetAllDomainsEnabledTests: RouteManagerTestCase {
 
     override func setUp() {
         super.setUp()
@@ -141,9 +162,7 @@ final class SetAllDomainsEnabledTests: XCTestCase {
 }
 
 @MainActor
-final class AddInverseDomainIntegrationTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class AddInverseDomainIntegrationTests: RouteManagerTestCase {
 
     override func setUp() {
         super.setUp()
@@ -181,9 +200,7 @@ final class AddInverseDomainIntegrationTests: XCTestCase {
 }
 
 @MainActor
-final class ToggleInverseDomainTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class ToggleInverseDomainTests: RouteManagerTestCase {
 
     override func setUp() {
         super.setUp()
@@ -203,9 +220,7 @@ final class ToggleInverseDomainTests: XCTestCase {
 }
 
 @MainActor
-final class SetAllInverseDomainsTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class SetAllInverseDomainsTests: RouteManagerTestCase {
 
     override func setUp() {
         super.setUp()
@@ -232,9 +247,7 @@ final class SetAllInverseDomainsTests: XCTestCase {
 }
 
 @MainActor
-final class CustomServiceTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class CustomServiceTests: RouteManagerTestCase {
 
     override func setUp() {
         super.setUp()
@@ -263,7 +276,6 @@ final class CustomServiceTests: XCTestCase {
             return
         }
         rm.removeCustomService(svc.id)
-        // removeCustomService dispatches an async Task; give it time to complete
         try await Task.sleep(nanoseconds: 200_000_000)
         XCTAssertFalse(rm.config.services.contains(where: { $0.id == svc.id }))
     }
@@ -283,9 +295,7 @@ final class CustomServiceTests: XCTestCase {
 }
 
 @MainActor
-final class ToggleServiceTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class ToggleServiceTests: RouteManagerTestCase {
 
     func testToggleBuiltInService() {
         guard let first = rm.config.services.first else {
@@ -301,9 +311,7 @@ final class ToggleServiceTests: XCTestCase {
 }
 
 @MainActor
-final class SetRoutingModeTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class SetRoutingModeTests: RouteManagerTestCase {
 
     func testSetRoutingModeToVPNOnly() {
         rm.setRoutingMode(.vpnOnly)
@@ -325,9 +333,7 @@ final class SetRoutingModeTests: XCTestCase {
 }
 
 @MainActor
-final class ExportImportConfigTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class ExportImportConfigTests: RouteManagerTestCase {
 
     func testExportConfigReturnsURL() {
         let url = rm.exportConfig()
@@ -372,9 +378,7 @@ final class ExportImportConfigTests: XCTestCase {
 }
 
 @MainActor
-final class SaveLoadConfigTests: XCTestCase {
-
-    private var rm: RouteManager { RouteManager.shared }
+final class SaveLoadConfigTests: RouteManagerTestCase {
 
     func testSaveConfigDoesNotCrash() {
         rm.saveConfig()
@@ -390,8 +394,6 @@ final class SaveLoadConfigTests: XCTestCase {
         rm.config.checkInterval = 0
         rm.loadConfig()
         XCTAssertEqual(rm.config.checkInterval, 999)
-        rm.config.checkInterval = 300
-        rm.saveConfig()
     }
 }
 
@@ -400,7 +402,6 @@ final class DetectedDNSDisplayTests: XCTestCase {
 
     func testDetectedDNSServerDisplayDefaultNil() {
         let display = RouteManager.shared.detectedDNSServerDisplay
-        // May or may not be nil depending on state, just check it doesn't crash
         _ = display
     }
 }