[camera_avfoundation] Test utils and mocks swift migration - part 2 (flutter#8892)

Migrates camera test utils and mocks as part of flutter/flutter#119109

Migrates to swift following mock classes:
- MockCameraDeviceDiscoverer
- MockDeviceOrientationProvider
- MockCapturePhotoOutput
- MockCaptureDeviceFormat
- MockFrameRateRange
- MockCaptureConnection
- MockGlobalEventApi
- MockFlutterTextureRegistry
- MockFlutterBinaryMessenger

## Pre-Review Checklist

[^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.

Author: RobertOdrowaz

packages/camera/camera_avfoundation/example/ios/Runner.xcodeproj/project.pbxproj

@@ -62,7 +62,7 @@ final class FLTCamExposureTests: XCTestCase {
   func testSetExposurePoint_setsExposurePointOfInterest() {
     let (camera, mockDevice, mockDeviceOrientationProvider) = createCamera()
     // UI is currently in landscape left orientation.
-    mockDeviceOrientationProvider.orientation = .landscapeLeft
+    mockDeviceOrientationProvider.orientationStub = { .landscapeLeft }
     // Exposure point of interest is supported.
     mockDevice.isExposurePointOfInterestSupported = true
 
@@ -87,7 +87,7 @@ final class FLTCamExposureTests: XCTestCase {
   func testSetExposurePoint_returnsError_ifNotSupported() {
     let (camera, mockDevice, mockDeviceOrientationProvider) = createCamera()
     // UI is currently in landscape left orientation.
-    mockDeviceOrientationProvider.orientation = .landscapeLeft
+    mockDeviceOrientationProvider.orientationStub = { .landscapeLeft }
     // Exposure point of interest is not supported.
     mockDevice.isExposurePointOfInterestSupported = false
 

packages/camera/camera_avfoundation/example/ios/RunnerTests/FLTCamExposureTests.swift

@@ -122,7 +122,7 @@ final class FLTCamSetFocusModeTests: XCTestCase {
   func testSetFocusPointWithResult_SetsFocusPointOfInterest() {
     let (camera, mockDevice, mockDeviceOrientationProvider) = createCamera()
     // UI is currently in landscape left orientation.
-    mockDeviceOrientationProvider.orientation = .landscapeLeft
+    mockDeviceOrientationProvider.orientationStub = { .landscapeLeft }
     // Focus point of interest is supported.
     mockDevice.isFocusPointOfInterestSupported = true
 
@@ -143,7 +143,7 @@ final class FLTCamSetFocusModeTests: XCTestCase {
   func testSetFocusPoint_WhenNotSupported_ReturnsError() {
     let (camera, mockDevice, mockDeviceOrientationProvider) = createCamera()
     // UI is currently in landscape left orientation.
-    mockDeviceOrientationProvider.orientation = .landscapeLeft
+    mockDeviceOrientationProvider.orientationStub = { .landscapeLeft }
     // Focus point of interest is not supported.
     mockDevice.isFocusPointOfInterestSupported = false
 

packages/camera/camera_avfoundation/example/ios/RunnerTests/FLTCamFocusTests.swift

@@ -0,0 +1,25 @@
+// 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.
+
+/// Mock implementation of `FLTCameraDeviceDiscovering` protocol which allows injecting a custom
+/// implementation for session discovery.
+final class MockCameraDeviceDiscoverer: NSObject, FLTCameraDeviceDiscovering {
+  var discoverySessionStub:
+    (
+      (
+        _ deviceTypes: [AVCaptureDevice.DeviceType],
+        _ mediaType: AVMediaType,
+        _ position: AVCaptureDevice.Position
+      ) -> [NSObject & FLTCaptureDevice]?
+    )?
+
+  /// A stub that replaces the default implementation of
+  /// `discoverySessionWithDeviceTypes:mediaType:position`.
+  func discoverySession(
+    withDeviceTypes deviceTypes: [AVCaptureDevice.DeviceType], mediaType: AVMediaType,
+    position: AVCaptureDevice.Position
+  ) -> [FLTCaptureDevice] {
+    return discoverySessionStub?(deviceTypes, mediaType, position) ?? []
+  }
+}

packages/camera/camera_avfoundation/example/ios/RunnerTests/Mocks/MockCameraDeviceDiscoverer.h

@@ -0,0 +1,22 @@
+// 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.
+
+/// A mock implementation of `FLTCaptureConnection` that allows injecting a custom implementation.
+final class MockCaptureConnection: NSObject, FLTCaptureConnection {
+  var setVideoOrientationStub: ((AVCaptureVideoOrientation) -> Void)?
+
+  var connection: AVCaptureConnection {
+    preconditionFailure("Attempted to access unimplemented property: connection")
+  }
+  var isVideoMirrored = false
+  var videoOrientation: AVCaptureVideoOrientation {
+    get { AVCaptureVideoOrientation.portrait }
+    set {
+      setVideoOrientationStub?(newValue)
+    }
+  }
+  var inputPorts: [AVCaptureInput.Port] = []
+  var isVideoMirroringSupported = false
+  var isVideoOrientationSupported = false
+}