Test coverage for pfw tool

.gitignore

@@ -60,3 +60,5 @@ fastlane/report.xml
 fastlane/Preview.html
 fastlane/screenshots/**/*.png
 fastlane/test_output
+
+*.DS_STORE

.swiftpm/xcode/xcshareddata/xcschemes/pfw.xcscheme

@@ -0,0 +1,96 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "2620"
+   version = "1.7">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES"
+      buildArchitectures = "Automatic">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "pfw"
+               BuildableName = "pfw"
+               BlueprintName = "pfw"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      shouldAutocreateTestPlan = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "pfwTests"
+               BuildableName = "pfwTests"
+               BlueprintName = "pfwTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "pfw"
+            BuildableName = "pfw"
+            BlueprintName = "pfw"
+            ReferencedContainer = "container:">
+         </BuildableReference>
+      </BuildableProductRunnable>
+      <CommandLineArguments>
+         <CommandLineArgument
+            argument = "--version"
+            isEnabled = "YES">
+         </CommandLineArgument>
+      </CommandLineArguments>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "pfw"
+            BuildableName = "pfw"
+            BlueprintName = "pfw"
+            ReferencedContainer = "container:">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

Package.swift

@@ -9,15 +9,33 @@ let package = Package(
   ],
   dependencies: [
     .package(url: "https://github.com/apple/swift-argument-parser", from: "1.5.0"),
+    .package(url: "https://github.com/pointfreeco/swift-concurrency-extras", from: "1.0.0"),
+    .package(url: "https://github.com/pointfreeco/swift-custom-dump", from: "1.0.0"),
+    .package(url: "https://github.com/pointfreeco/swift-dependencies", from: "1.0.0"),
+    .package(url: "https://github.com/pointfreeco/swift-snapshot-testing", from: "1.0.0"),
     .package(url: "https://github.com/weichsel/ZIPFoundation", from: "0.9.20"),
   ],
   targets: [
     .executableTarget(
       name: "pfw",
       dependencies: [
         .product(name: "ArgumentParser", package: "swift-argument-parser"),
+        .product(name: "ConcurrencyExtras", package: "swift-concurrency-extras"),
+        .product(name: "CustomDump", package: "swift-custom-dump"),
+        .product(name: "Dependencies", package: "swift-dependencies"),
         .product(name: "ZIPFoundation", package: "ZIPFoundation")
       ]
+    ),
+    .testTarget(
+      name: "pfwTests",
+      dependencies: [
+        .product(name: "ConcurrencyExtras", package: "swift-concurrency-extras"),
+        .product(name: "CustomDump", package: "swift-custom-dump"),
+        .product(name: "Dependencies", package: "swift-dependencies"),
+        .product(name: "DependenciesTestSupport", package: "swift-dependencies"),
+        .product(name: "InlineSnapshotTesting", package: "swift-snapshot-testing"),
+        "pfw"
+      ]
     )
   ],
   swiftLanguageModes: [.v6]

Sources/pfw/Dependencies/Auth.swift

@@ -0,0 +1,126 @@
+import ArgumentParser
+import Dependencies
+import Foundation
+import Synchronization
+
+#if canImport(Network)
+  import Network
+#endif
+
+protocol Auth: Sendable {
+  func start() async throws -> URL
+  func waitForToken() async throws -> String
+}
+
+  enum AuthKey: DependencyKey {
+#if canImport(Network)
+    static var liveValue: any Auth { try! LocalAuthServer() }
+#endif
+  }
+
+extension DependencyValues {
+  var auth: any Auth {
+    get { self[AuthKey.self] }
+    set { self[AuthKey.self] = newValue }
+  }
+}
+
+#if canImport(Network)
+  actor LocalAuthServer: Auth {
+    private let listener: NWListener
+    private let queue = DispatchQueue(label: "pfw.auth.server")
+    private var tokenContinuation: CheckedContinuation<String, Error>?
+
+    init() throws {
+      listener = try NWListener(using: .tcp, on: .any)
+    }
+
+    func start() async throws -> URL {
+      let hasStarted = Mutex(false)
+      listener.stateUpdateHandler = { state in
+        guard state == .ready
+        else { return }
+        hasStarted.withLock { $0 = true }
+      }
+      listener.newConnectionHandler = { [weak self] connection in
+        Task {
+          connection.start(queue: self?.queue ?? .main)
+          await self?.receiveToken(from: connection)
+        }
+      }
+      listener.start(queue: queue)
+      while !hasStarted.withLock(\.self) {
+        try await Task.sleep(for: .seconds(0.1))
+        // TODO: Timeout if takes too long
+      }
+      guard let port = listener.port else {
+        throw ValidationError("Unable to determine callback port.")
+      }
+      return URL(string: "http://127.0.0.1:\(port)/callback")!
+    }
+
+    func waitForToken() async throws -> String {
+      try await withCheckedThrowingContinuation { continuation in
+        tokenContinuation = continuation
+      }
+    }
+
+    private func receiveToken(from connection: NWConnection) {
+      connection.receive(minimumIncompleteLength: 1, maximumLength: 8_192) {
+        [weak self] data, _, _, error in
+        Task {
+          if let error {
+            await self?.finish(with: .failure(error))
+            connection.cancel()
+            return
+          }
+          guard let data, let request = String(data: data, encoding: .utf8) else {
+            await self?.finish(with: .failure(ValidationError("Invalid request.")))
+            connection.cancel()
+            return
+          }
+          let token = Self.token(from: request)
+          if let token {
+            await self?.respond(connection: connection, success: true)
+            await self?.finish(with: .success(token))
+          } else {
+            await self?.respond(connection: connection, success: false)
+            await self?.finish(with: .failure(ValidationError("Missing token in redirect.")))
+          }
+          connection.cancel()
+        }
+      }
+    }
+
+    private func respond(connection: NWConnection, success: Bool) {
+      let message =
+        success
+        ? "You can return to the terminal. Login complete."
+        : "Login failed. Please return to the terminal."
+      let body = "<html><body><p>\(message)</p></body></html>"
+      let response = """
+        HTTP/1.1 200 OK\r
+        Content-Type: text/html; charset=utf-8\r
+        Content-Length: \(body.utf8.count)\r
+        Connection: close\r
+        \r
+        \(body)
+        """
+      connection.send(content: response.data(using: .utf8), completion: .contentProcessed { _ in })
+    }
+
+    private func finish(with result: Result<String, Error>) {
+      tokenContinuation?.resume(with: result)
+      tokenContinuation = nil
+      listener.cancel()
+    }
+
+    private static func token(from request: String) -> String? {
+      return String(
+        request
+          .dropFirst("GET /callback?token=".count)
+          .prefix(while: { $0 != " " })
+      )
+    }
+  }
+#endif