[local_auth] Convert native unit tests to Swift (#6779)

Converts native unit tests from Objective-C to Swift, as a first step toward an eventual plugin conversion. Since OCMock usage was removed in a previous PR, the tests are converted essentially directly (the rewrites were largely mechanical syntax replacement), without any changes needed to production code.

There are a few places where interacting with the Pigeon-generated Obj-C is somewhat awkward because the NSError signature isn't auto-converting to `throw` in cases where we use `NSNumber` wrapping, but all that will get cleaned up when we switch the plugin over to Swift Pigeon generation and have idiomatic Swift APIs that the tests will be calling instead.

Fixes a couple of false positives in the repo tooling surfaced by this PR:
- `darwin/Tests/` wasn't recognized as a test directory.
- Swift tests weren't recognized as exempt from requiring Swift entries in the podspec.

Part of flutter/flutter#119104

packages/local_auth/local_auth_darwin/darwin/Tests/FLALocalAuthPluginTests.swift

@@ -0,0 +1,397 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import Flutter
+import XCTest
+
+@testable import local_auth_darwin
+
+// Set a long timeout to avoid flake due to slow CI.
+private let timeout: TimeInterval = 30.0
+
+/// A context factory that returns preset contexts.
+final class StubAuthContextFactory: NSObject, FLADAuthContextFactory {
+  var contexts: [FLADAuthContext]
+  init(contexts: [FLADAuthContext]) {
+    self.contexts = contexts
+  }
+
+  func createAuthContext() -> FLADAuthContext {
+    XCTAssert(self.contexts.count > 0, "Insufficient test contexts provided")
+    return self.contexts.removeFirst()
+  }
+}
+
+final class StubAuthContext: NSObject, FLADAuthContext {
+  /// Whether calls to this stub are expected to be for biometric authentication.
+  ///
+  /// While this object could be set up to return different values for different policies, in
+  /// practice only one policy is needed by any given test, so this just allows asserting that the
+  /// code is calling with the intended policy.
+  var expectBiometrics = false
+  /// The error to return from canEvaluatePolicy.
+  var canEvaluateError: NSError?
+  /// The value to return from evaluatePolicy:error:.
+  var evaluateResponse = false
+  /// The error to return from evaluatePolicy:error:.
+  var evaluateError: NSError?
+
+  // Overridden as read-write to allow stubbing.
+  var biometryType: LABiometryType = .none
+  var localizedFallbackTitle: String?
+
+  func canEvaluatePolicy(_ policy: LAPolicy) throws {
+    XCTAssertEqual(
+      policy,
+      expectBiometrics
+        ? LAPolicy.deviceOwnerAuthenticationWithBiometrics
+        : LAPolicy.deviceOwnerAuthentication)
+    if let canEvaluateError = canEvaluateError {
+      throw canEvaluateError
+    }
+  }
+
+  func evaluatePolicy(
+    _ policy: LAPolicy, localizedReason: String, reply: @escaping (Bool, Error?) -> Void
+  ) {
+    XCTAssertEqual(
+      policy,
+      expectBiometrics
+        ? LAPolicy.deviceOwnerAuthenticationWithBiometrics
+        : LAPolicy.deviceOwnerAuthentication)
+    // evaluatePolicy:localizedReason:reply: calls back on an internal queue, which is not
+    // guaranteed to be on the main thread. Ensure that's handled correctly by calling back on
+    // a background thread.
+    DispatchQueue.global(qos: .background).async {
+      reply(self.evaluateResponse, self.evaluateError)
+    }
+  }
+}
+
+// MARK: -
+
+class FLALocalAuthPluginTests: XCTestCase {
+
+  func testSuccessfullAuthWithBiometrics() throws {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    let strings = createAuthStrings()
+    stubAuthContext.expectBiometrics = true
+    stubAuthContext.evaluateResponse = true
+    let expectation = expectation(description: "Result is called")
+    plugin.authenticate(
+      with: FLADAuthOptions.make(
+        withBiometricOnly: true,
+        sticky: false,
+        useErrorDialogs: false),
+      strings: strings
+    ) { resultDetails, error in
+      XCTAssertTrue(Thread.isMainThread)
+      XCTAssertEqual(resultDetails?.result, FLADAuthResult.success)
+      XCTAssertNil(error)
+      expectation.fulfill()
+    }
+    self.waitForExpectations(timeout: timeout)
+  }
+
+  func testSuccessfullAuthWithoutBiometrics() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    let strings = createAuthStrings()
+    stubAuthContext.evaluateResponse = true
+
+    let expectation = expectation(description: "Result is called")
+    plugin.authenticate(
+      with: FLADAuthOptions.make(
+        withBiometricOnly: false,
+        sticky: false,
+        useErrorDialogs: false),
+      strings: strings
+    ) { resultDetails, error in
+      XCTAssertTrue(Thread.isMainThread)
+      XCTAssertEqual(resultDetails?.result, FLADAuthResult.success)
+      XCTAssertNil(error)
+      expectation.fulfill()
+    }
+    self.waitForExpectations(timeout: timeout)
+  }
+
+  func testFailedAuthWithBiometrics() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    let strings = createAuthStrings()
+    stubAuthContext.expectBiometrics = true
+    stubAuthContext.evaluateError = NSError(
+      domain: "error", code: LAError.authenticationFailed.rawValue)
+
+    let expectation = expectation(description: "Result is called")
+    plugin.authenticate(
+      with: FLADAuthOptions.make(
+        withBiometricOnly: true,
+        sticky: false,
+        useErrorDialogs: false),
+      strings: strings
+    ) { resultDetails, error in
+      XCTAssertTrue(Thread.isMainThread)
+      // TODO(stuartmorgan): Fix this; this was the pre-Pigeon-migration
+      // behavior, so is preserved as part of the migration, but a failed
+      // authentication should return failure, not an error that results in a
+      // PlatformException.
+      XCTAssertEqual(resultDetails?.result, FLADAuthResult.errorNotAvailable)
+      XCTAssertNil(error)
+      expectation.fulfill()
+    }
+    self.waitForExpectations(timeout: timeout)
+  }
+
+  func testFailedWithUnknownErrorCode() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    let strings = createAuthStrings()
+    stubAuthContext.evaluateError = NSError(domain: "error", code: 99)
+
+    let expectation = expectation(description: "Result is called")
+    plugin.authenticate(
+      with: FLADAuthOptions.make(
+        withBiometricOnly: false,
+        sticky: false,
+        useErrorDialogs: false),
+      strings: strings
+    ) { resultDetails, error in
+      XCTAssertTrue(Thread.isMainThread)
+      XCTAssertEqual(resultDetails?.result, FLADAuthResult.errorNotAvailable)
+      XCTAssertNil(error)
+      expectation.fulfill()
+    }
+    self.waitForExpectations(timeout: timeout)
+  }
+
+  func testSystemCancelledWithoutStickyAuth() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    let strings = createAuthStrings()
+    stubAuthContext.evaluateError = NSError(domain: "error", code: LAError.systemCancel.rawValue)
+
+    let expectation = expectation(description: "Result is called")
+    plugin.authenticate(
+      with: FLADAuthOptions.make(
+        withBiometricOnly: false,
+        sticky: false,
+        useErrorDialogs: false),
+      strings: strings
+    ) { resultDetails, error in
+      XCTAssertTrue(Thread.isMainThread)
+      XCTAssertEqual(resultDetails?.result, FLADAuthResult.failure)
+      XCTAssertNil(error)
+      expectation.fulfill()
+    }
+    self.waitForExpectations(timeout: timeout)
+  }
+
+  func testFailedAuthWithoutBiometrics() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    let strings = createAuthStrings()
+    stubAuthContext.evaluateError = NSError(
+      domain: "error", code: LAError.authenticationFailed.rawValue)
+
+    let expectation = expectation(description: "Result is called")
+    plugin.authenticate(
+      with: FLADAuthOptions.make(
+        withBiometricOnly: false,
+        sticky: false,
+        useErrorDialogs: false),
+      strings: strings
+    ) { resultDetails, error in
+      XCTAssertTrue(Thread.isMainThread)
+      // TODO(stuartmorgan): Fix this; this was the pre-Pigeon-migration
+      // behavior, so is preserved as part of the migration, but a failed
+      // authentication should return failure, not an error that results in a
+      // PlatformException.
+      XCTAssertEqual(resultDetails?.result, FLADAuthResult.errorNotAvailable)
+      XCTAssertNil(error)
+      expectation.fulfill()
+    }
+    self.waitForExpectations(timeout: timeout)
+  }
+
+  func testLocalizedFallbackTitle() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    let strings = createAuthStrings()
+    strings.localizedFallbackTitle = "a title"
+    stubAuthContext.evaluateResponse = true
+
+    let expectation = expectation(description: "Result is called")
+    plugin.authenticate(
+      with: FLADAuthOptions.make(
+        withBiometricOnly: false,
+        sticky: false,
+        useErrorDialogs: false),
+      strings: strings
+    ) { resultDetails, error in
+      XCTAssertEqual(
+        stubAuthContext.localizedFallbackTitle,
+        strings.localizedFallbackTitle)
+      expectation.fulfill()
+    }
+    self.waitForExpectations(timeout: timeout)
+  }
+
+  func testSkippedLocalizedFallbackTitle() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    let strings = createAuthStrings()
+    strings.localizedFallbackTitle = nil
+    stubAuthContext.evaluateResponse = true
+
+    let expectation = expectation(description: "Result is called")
+    plugin.authenticate(
+      with: FLADAuthOptions.make(
+        withBiometricOnly: false,
+        sticky: false,
+        useErrorDialogs: false),
+      strings: strings
+    ) { resultDetails, error in
+      XCTAssertNil(stubAuthContext.localizedFallbackTitle)
+      expectation.fulfill()
+    }
+    self.waitForExpectations(timeout: timeout)
+  }
+
+  func testDeviceSupportsBiometrics_withEnrolledHardware() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    stubAuthContext.expectBiometrics = true
+
+    var error: FlutterError?
+    let result = plugin.deviceCanSupportBiometricsWithError(&error)
+    XCTAssertTrue(result!.boolValue)
+    XCTAssertNil(error)
+  }
+
+  func testDeviceSupportsBiometrics_withNonEnrolledHardware() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    stubAuthContext.expectBiometrics = true
+    stubAuthContext.canEvaluateError = NSError(
+      domain: "error", code: LAError.biometryNotEnrolled.rawValue)
+
+    var error: FlutterError?
+    let result = plugin.deviceCanSupportBiometricsWithError(&error)
+    XCTAssertTrue(result!.boolValue)
+    XCTAssertNil(error)
+  }
+
+  func testDeviceSupportsBiometrics_withNoBiometricHardware() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    stubAuthContext.expectBiometrics = true
+    stubAuthContext.canEvaluateError = NSError(domain: "error", code: 0)
+
+    var error: FlutterError?
+    let result = plugin.deviceCanSupportBiometricsWithError(&error)
+    XCTAssertFalse(result!.boolValue)
+    XCTAssertNil(error)
+  }
+
+  func testGetEnrolledBiometricsWithFaceID() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    stubAuthContext.expectBiometrics = true
+    stubAuthContext.biometryType = .faceID
+
+    var error: FlutterError?
+    let result = plugin.getEnrolledBiometricsWithError(&error)
+    XCTAssertEqual(result!.count, 1)
+    XCTAssertEqual(result![0].value, FLADAuthBiometric.face)
+    XCTAssertNil(error)
+  }
+
+  func testGetEnrolledBiometricsWithTouchID() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    stubAuthContext.expectBiometrics = true
+    stubAuthContext.biometryType = .touchID
+
+    var error: FlutterError?
+    let result = plugin.getEnrolledBiometricsWithError(&error)
+    XCTAssertEqual(result!.count, 1)
+    XCTAssertEqual(result![0].value, FLADAuthBiometric.fingerprint)
+    XCTAssertNil(error)
+  }
+
+  func testGetEnrolledBiometricsWithoutEnrolledHardware() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    stubAuthContext.expectBiometrics = true
+    stubAuthContext.canEvaluateError = NSError(
+      domain: "error", code: LAError.biometryNotEnrolled.rawValue)
+
+    var error: FlutterError?
+    let result = plugin.getEnrolledBiometricsWithError(&error)
+    XCTAssertTrue(result!.isEmpty)
+    XCTAssertNil(error)
+  }
+
+  func testIsDeviceSupportedHandlesSupported() {
+    let stubAuthContext = StubAuthContext()
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    var error: FlutterError?
+    let result = plugin.isDeviceSupportedWithError(&error)
+    XCTAssertTrue(result!.boolValue)
+    XCTAssertNil(error)
+  }
+
+  func testIsDeviceSupportedHandlesUnsupported() {
+    let stubAuthContext = StubAuthContext()
+    // An arbitrary error to cause canEvaluatePolicy to return false.
+    stubAuthContext.canEvaluateError = NSError(domain: "error", code: 1)
+    let plugin = FLALocalAuthPlugin(
+      contextFactory: StubAuthContextFactory(contexts: [stubAuthContext]))
+
+    var error: FlutterError?
+    let result = plugin.isDeviceSupportedWithError(&error)
+    XCTAssertFalse(result!.boolValue)
+    XCTAssertNil(error)
+  }
+
+  // Creates an FLADAuthStrings with placeholder values.
+  func createAuthStrings() -> FLADAuthStrings {
+    return FLADAuthStrings.make(
+      withReason: "a reason", lockOut: "locked out", goToSettingsButton: "Go To Settings",
+      goToSettingsDescription: "Settings", cancelButton: "Cancel", localizedFallbackTitle: nil)
+  }
+
+}