Address reviews and add tests for manual code.

src/CoreVideo/CVBuffer.cs

@@ -27,6 +27,7 @@
 //
 using System;
 using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
 using CoreFoundation;
 using ObjCRuntime;
 using Foundation;
@@ -150,9 +151,9 @@ public NSObject GetAttachment (NSString key, out CVAttachmentMode attachmentMode
 			if (key == null)
 				throw new ArgumentNullException ("key");
 			if (PlatformHelper.CheckSystemVersion (12, 0))
-				return Runtime.GetNSObject (CVBufferCopyAttachment (handle, key.Handle, out attachmentMode));
+				return Runtime.GetINativeObject<NSObject> (CVBufferCopyAttachment (handle, key.Handle, out attachmentMode), true);
 			else
-				return Runtime.GetNSObject (CVBufferGetAttachment (handle, key.Handle, out attachmentMode));
+				return Runtime.GetINativeObject<NSObject> (CVBufferGetAttachment (handle, key.Handle, out attachmentMode), false);
 		}
 #endif
 
@@ -177,8 +178,8 @@ public NSDictionary GetAttachments (CVAttachmentMode attachmentMode)
 #elif MONOMAC
 			if (PlatformHelper.CheckSystemVersion (12, 0))
 #endif
-				return (NSDictionary) Runtime.GetNSObject (CVBufferCopyAttachments (handle, attachmentMode));
-			return (NSDictionary) Runtime.GetNSObject (CVBufferGetAttachments (handle, attachmentMode));
+				return Runtime.GetINativeObject<NSDictionary> (CVBufferCopyAttachments (handle, attachmentMode), true);
+			return Runtime.GetINativeObject<NSDictionary> (CVBufferGetAttachments (handle, attachmentMode), false);
 		}
 
 		// There is some API that needs a more strongly typed version of a NSDictionary
@@ -232,7 +233,7 @@ public void SetAttachments (NSDictionary theAttachments, CVAttachmentMode attach
 		[SupportedOSPlatform ("macos12.0")]
 #endif
 		[DllImport (Constants.CoreVideoLibrary)]
-		[return: MarshalAs(UnmanagedType.U1)]
+		[return: MarshalAs (UnmanagedType.U1)]
 		static extern bool CVBufferHasAttachment (/* CVBufferRef */ IntPtr buffer, /* CFStringRef */ IntPtr key);
 
 #if !NET

tests/monotouch-test/CoreVideo/CVDisplayLinkTest.cs

@@ -0,0 +1,111 @@
+#if __MACOS__
+using System;
+using CoreGraphics;
+using Foundation;
+using NUnit.Framework;
+using Foundation;
+using ObjCRuntime;
+using CoreVideo;
+
+namespace MonoTouchFixtures.CoreVideo {
+
+	[TestFixture]
+	[Preserve (AllMembers = true)]
+	public class CVDisplayLinkTest {
+		int? mainDisplayId = null;
+
+		[SetUp]
+		public void SetUp ()
+		{
+			// we need to have access to the media display to be able to perform
+			// the displaylink tests
+			mainDisplayId = CGDisplay.MainDisplayID;
+		}
+
+		[TearDown]
+		public void TearDown ()
+		{
+			mainDisplayId = null;
+		}
+
+		[Test]
+		public void CreateFromDisplayIdValidIdTest ()
+		{
+			TestRuntime.AssertSystemVersion (PlatformName.MacOSX, 12, 0);
+			Assert.DoesNotThrow (() => {
+				using var displayLink = CVDisplayLink.CreateFromDisplayId ((uint) CGDisplay.MainDisplayID);
+				Assert.NotNull (displayLink, "Not null");
+				Assert.AreEqual (CGDisplay.MainDisplayID,  displayLink.GetCurrentDisplay (), "DisplayId");
+			}, "Throws");
+		}
+
+		[Test]
+		public void CreateFromDisplayWrongIdTest ()
+		{
+			TestRuntime.AssertSystemVersion (PlatformName.MacOSX, 12, 0);
+			Assert.DoesNotThrow (() => {
+				using var displayLink = CVDisplayLink.CreateFromDisplayId (UInt32.MaxValue);
+				Assert.Null (displayLink, "null");
+			}, "Throws");
+		}
+
+		[Test]
+		public void CreateFromDisplayIdsTest ()
+		{
+			TestRuntime.AssertSystemVersion (PlatformName.MacOSX, 12, 0);
+			// we might not have more than one display, therefore we will use an array 
+			// with a single one, there is nothing in the docs that say that we cannot do that
+			Assert.DoesNotThrow (() => {
+				using var displayLink = CVDisplayLink.CreateFromDisplayIds (new []{ (uint) CGDisplay.MainDisplayID});
+				Assert.Null (displayLink, "null");
+			}, "Throws");
+		}
+
+		[Test]
+		public void CreateFromOpenGLMaskTest ()
+		{
+			TestRuntime.AssertSystemVersion (PlatformName.MacOSX, 12, 0);
+			var openGLMask = CGDisplay.GetOpenGLDisplayMask (CGDisplay.MainDisplayID);
+			Assert.DoesNotThrow (() => {
+				using var displayLink = CVDisplayLink.CreateFromOpenGLMask ((uint) openGLMask);
+				Assert.NotNull (displayLink, "Not null");
+			}, "Throws");
+		}
+
+		[Test]
+		public void DefaultconstructorTest () => Assert.DoesNotThrow (() => {
+			using var displayLink = new CVDisplayLink ();
+		});
+
+		[Test]
+		public void SetCurrentDisplayOpenGLTest () => Assert.DoesNotThrow (() => {
+			using var displayLink = new CVDisplayLink ();
+			displayLink.SetCurrentDisplay (CGDisplay.MainDisplayID);
+		});
+
+		[Test]
+		public void GetCurrentDisplayTest () => Assert.DoesNotThrow (() => {
+			using var displayLink = new CVDisplayLink ();
+			Assert.AreEqual (CGDisplay.MainDisplayID,  displayLink.GetCurrentDisplay ());
+		});
+
+		[Test]
+		public void GetTypeIdTest ()
+		{
+			TestRuntime.AssertSystemVersion (PlatformName.MacOSX, 12, 0);
+			Assert.DoesNotThrow (() => {
+				CVDisplayLink.GetTypeId ();
+			}, "Throws");
+		}
+
+		[Test]
+		public void TryTranslateTimeValidTest ()
+		{
+			TestRuntime.AssertSystemVersion (PlatformName.MacOSX, 12, 0);
+			using var displayLink = new CVDisplayLink ();
+			displayLink.GetCurrentTime (out var timeStamp);
+			Assert.True (displayLink.TryTranslateTime (timeStamp, out var _));
+		}
+	}
+}
+#endif