Separate bonjour concerns in PrinterRequestManager into BonjourBrowser, add unit test for BonjourBrowser

Soyuz/ViewModels/BonjourBrowser.swift

@@ -0,0 +1,75 @@
+//
+//  BonjourBrowser.swift
+//  Soyuz
+//
+//  Created by maddiefuzz on 3/20/23.
+//
+
+import Foundation
+import Network
+
+// Protocol defining minimal API for network discovery
+// MARK: Net Discovery Protocol
+protocol NetworkDiscoveryEngine {
+    func startScan(queue: DispatchQueue)
+    
+    func setBrowseResultsChangedHandler(_ handler: @escaping ((Set<NWBrowser.Result>, Set<NWBrowser.Result.Change>) -> Void))
+    func setStateUpdateHandler(_ handler: @escaping ((NWBrowser.State) -> Void))
+}
+
+extension NWBrowser: NetworkDiscoveryEngine {
+    
+    func startScan(queue: DispatchQueue) {
+        start(queue: queue)
+    }
+    
+    func setBrowseResultsChangedHandler(_ handler: @escaping ((Set<NWBrowser.Result>, Set<NWBrowser.Result.Change>) -> Void)) {
+        self.browseResultsChangedHandler = handler
+    }
+
+    func setStateUpdateHandler(_ handler: @escaping ((State) -> Void)) {
+        self.stateUpdateHandler = handler
+    }
+}
+
+// MARK: BonjourBrowser
+
+class BonjourBrowser: ObservableObject {
+    @Published var NDEngineResults: [NWBrowser.Result] = []
+    
+    private let nwBrowser: NetworkDiscoveryEngine
+    var connection: NWConnection!
+    
+    // TEMPORARY
+//    var bonjourListener: NWListener?
+
+    init(browser: NetworkDiscoveryEngine = NWBrowser(for: .bonjourWithTXTRecord(type: "_moonraker._tcp", domain: "local."), using: .tcp)) {
+        nwBrowser = browser
+        // Bonjour browser results changed handler
+        nwBrowser.setBrowseResultsChangedHandler({ (newResults, changes) in
+            print("[update] Results changed.")
+            self.NDEngineResults.removeAll()
+            newResults.forEach { result in
+                print(result)
+                self.NDEngineResults.append(result)
+            }
+        })
+        
+        // Bonjour browser state update handler
+        nwBrowser.setStateUpdateHandler({ newState in
+            switch newState {
+            case .failed(let error):
+                print("[error] nwbrowser: \(error)")
+            case .ready:
+                print("[ready] nwbrowser")
+            case .setup:
+                print("[setup] nwbrowser")
+            default:
+                break
+            }
+        })
+        
+        nwBrowser.startScan(queue: DispatchQueue.main)
+    }
+    
+}