[tests][intro] Add checks for [Field] that should have [Notification] attributes (#1289)

Also:

* some refactoring to reduce the reflection usage for each field-based
  introspection tests;

* some fixes for existing bindings, mostly missing [Notification]

* removal of `unsafe` in the notification binding generation (not needed)

* Ignore the new test on XM until the API have been fixed

src/UIKit/UIWindow.cs

@@ -8,7 +8,7 @@
 // Copyright 2014, Xamarin Inc. All rights reserved.
 //
 
-#if !XAMCORE_2_0
+#if IOS
 
 using System;
 using XamCore.ObjCRuntime;
@@ -17,6 +17,7 @@ using XamCore.Foundation;
 
 namespace XamCore.UIKit {
 	public partial class UIWindow {
+#if !XAMCORE_2_0
 		// we already have a UIWindowLevel static class for the constants
 		[Obsolete ("Use UIWindowLevel.Normal")]
 		public const float LevelNormal = 0f;
@@ -26,6 +27,18 @@ namespace XamCore.UIKit {
 
 		[Obsolete ("Use UIWindowLevel.StatusBar")]
 		public const float LevelStatusBar = 1000f;
+#endif
+#if !XAMCORE_4_0
+		// duplicates from UIKeyboard without a [Notification]
+
+		public static NSString KeyboardDidChangeFrameNotification {
+			get { return UIKeyboard.DidChangeFrameNotification; }
+		}
+
+		public static NSString KeyboardWillChangeFrameNotification {
+			get { return UIKeyboard.WillChangeFrameNotification; }
+		}
+#endif
 	}
 }
 

src/generator.cs

@@ -6334,7 +6334,7 @@ public partial class Generator : IMemberGatherer {
 					if (HasAttribute (field_pi, typeof (NotificationAttribute)))
 						print ($"[Advice (\"Use {type.Name}.Notifications.Observe{GetNotificationName (field_pi)} helper method instead.\")]");
 					
-					print ("{0} static unsafe {1} {2}{3} {{", field_pi.IsInternal () ? "internal" : "public", fieldTypeName,
+					print ("{0} static {1} {2}{3} {{", field_pi.IsInternal () ? "internal" : "public", fieldTypeName,
 					       field_pi.Name,
 					       is_unified_internal ? "_" : "");
 					indent++;

src/homekit.cs

@@ -385,6 +385,7 @@ namespace XamCore.HomeKit {
 		[Field ("HMCharacteristicPropertyHidden")]
 		NSString Hidden { get; }
 
+		[Notification]
 		[Field ("HMCharacteristicPropertySupportsEventNotification")]
 		NSString SupportsEventNotification { get; }		
 	}

src/mediaplayer.cs

@@ -1227,10 +1227,12 @@ namespace XamCore.MediaPlayer {
 		UIImage VolumeWarningSliderImage { get; set; }
 
 		[Since (7,0)]
+		[Notification]
 		[Field ("MPVolumeViewWirelessRoutesAvailableDidChangeNotification")]
 		NSString WirelessRoutesAvailableDidChangeNotification { get; }
 
 		[Since (7,0)]
+		[Notification]
 		[Field ("MPVolumeViewWirelessRouteActiveDidChangeNotification")]
 		NSString WirelessRouteActiveDidChangeNotification { get; }
 	}	

src/uikit.cs

@@ -7045,16 +7045,6 @@ namespace XamCore.UIKit {
 		[Field ("UIWindowDidResignKeyNotification")]
 		[Notification]
 		NSString DidResignKeyNotification { get; }
-		
-		[NoTV]
-		[Since (5,0)]
-		[Field("UIKeyboardWillChangeFrameNotification")]
-		NSString KeyboardWillChangeFrameNotification { get; }
-		
-		[NoTV]
-		[Since (5,0)]
-		[Field("UIKeyboardDidChangeFrameNotification")]
-		NSString KeyboardDidChangeFrameNotification { get; }
 	}
 
 	[BaseType (typeof (UIView))]

tests/introspection/ApiFieldTest.cs

@@ -103,6 +103,83 @@ namespace Introspection {
 				return false;
 			}
 		}
+
+		static List<PropertyInfo> properties;
+
+		IEnumerable<PropertyInfo> AllProperties ()
+		{
+			if (properties != null)
+				return properties;
+
+			properties = new List<PropertyInfo> ();
+			foreach (Type t in Assembly.GetTypes ()) {
+				if (Skip (t) || SkipDueToAttribute (t))
+					continue;
+
+				foreach (var p in t.GetProperties (BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic)) {
+					// looking for properties with getters only
+					if (p.CanWrite || !p.CanRead)
+						continue;
+					if (SkipDueToAttribute (p))
+						continue;
+
+					properties.Add (p);
+				}
+			}
+			return properties;
+		}
+
+		[Test]
+#if MONOMAC
+		[Ignore ("Some API needs fixing - https://jenkins.mono-project.com/job/xamarin-macios-pr-builder/2188/Test_Report/")]
+#endif
+		public void Notifications ()
+		{
+			var failed_fields = new List<string> ();
+
+			Errors = 0;
+			int c = 0, n = 0;
+			foreach (var p in AllProperties ()) {
+				if (p.PropertyType.FullName != NSStringType)
+					continue;
+				
+				var f = p.GetCustomAttribute<FieldAttribute> ();
+				if (f == null)
+					continue;
+
+				var name = f.SymbolName;
+				if (!name.EndsWith ("Notification", StringComparison.Ordinal))
+					continue;
+
+				var nested = p.DeclaringType.GetNestedTypes ();
+				if (nested.Length == 0) {
+					ReportError (name);
+					failed_fields.Add (name);
+				} else {
+					bool found = false;
+					foreach (var nt in nested) {
+						if (nt.Name != "Notifications")
+							continue;
+						// look for the associated methods
+						name = "Observe" + p.Name;
+						if (name.EndsWith ("Notification", StringComparison.Ordinal))
+							name = name.Substring (0, name.Length - "Notification".Length);
+						foreach (var m in nt.GetMethods (BindingFlags.Static | BindingFlags.Public)) {
+							if (name == m.Name) {
+								found = true;
+								break;
+							}
+						}
+					}
+					if (!found) {
+						ReportError (name);
+						failed_fields.Add (name);
+					}
+				}
+				n++;
+			}
+			Assert.AreEqual (0, Errors, "{0} errors found in {1} fields validated: {2}", Errors, n, string.Join (", ", failed_fields));
+		}
 		
 		[Test]
 		public void NonNullNSStringFields ()
@@ -110,33 +187,18 @@ namespace Introspection {
 			var failed_fields = new List<string> ();
 
 			Errors = 0;
-			int c = 0, n = 0;
-			foreach (Type t in Assembly.GetTypes ()) {
-				if (Skip (t) || SkipDueToAttribute (t))
+			int n = 0;
+			foreach (var p in AllProperties ()) {
+				if (p.PropertyType.FullName != NSStringType)
 					continue;
 
-				if (LogProgress)
-					Console.WriteLine ("{0}. {1}", c++, t.FullName);
-
-				foreach (var p in t.GetProperties (BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic)) {
-					// looking for properties with getters only
-					if (p.CanWrite || !p.CanRead)
-						continue;
-					
-					if (p.PropertyType.FullName != NSStringType)
-						continue;
-
-					if (SkipDueToAttribute (p))
-						continue;
-
-					string name;
-					bool result = CheckAgainstNull (p, out name);
-					if (!result) {
-						ReportError (name);
-						failed_fields.Add (name);
-					}
-					n++;
+				string name;
+				bool result = CheckAgainstNull (p, out name);
+				if (!result) {
+					ReportError (name);
+					failed_fields.Add (name);
 				}
+				n++;
 			}
 			Assert.AreEqual (0, Errors, "{0} errors found in {1} fields validated: {2}", Errors, n, string.Join (", ", failed_fields));
 		}
@@ -147,39 +209,24 @@ namespace Introspection {
 			var failed_fields = new List<string> ();
 
 			Errors = 0;
-			int c = 0, n = 0;
-			foreach (Type t in Assembly.GetTypes ()) {
-				if (Skip (t) || SkipDueToAttribute (t))
+			int n = 0;
+			foreach (var p in AllProperties ()) {
+				var f = p.GetCustomAttribute<FieldAttribute> ();
+				if (f == null)
 					continue;
 
-				if (LogProgress)
-					Console.WriteLine ("{0}. {1}", c++, t.FullName);
+				string name = f.SymbolName;
+				if (Skip (name))
+					continue;
 
-				foreach (var p in t.GetProperties (BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic)) {
-					// looking for properties with getters only
-					if (p.CanWrite || !p.CanRead)
-						continue;
-
-					if (SkipDueToAttribute (p))
-						continue;
-
-					var f = p.GetCustomAttribute<FieldAttribute> ();
-					if (f == null)
-						continue;
-
-					string name = f.SymbolName;
-					if (Skip (name))
-						continue;
-
-					string path = FindLibrary (f.LibraryName);
-					IntPtr lib = Dlfcn.dlopen (path, 0);
-					if (Dlfcn.GetIndirect (lib, name) == IntPtr.Zero) {
-						ReportError ("Could not find the field '{0}' in {1}", name, path);
-						failed_fields.Add (name);
-					}
-					Dlfcn.dlclose (lib);
-					n++;
+				string path = FindLibrary (f.LibraryName);
+				IntPtr lib = Dlfcn.dlopen (path, 0);
+				if (Dlfcn.GetIndirect (lib, name) == IntPtr.Zero) {
+					ReportError ("Could not find the field '{0}' in {1}", name, path);
+					failed_fields.Add (name);
 				}
+				Dlfcn.dlclose (lib);
+				n++;
 			}
 			Assert.AreEqual (0, Errors, "{0} errors found in {1} fields validated: {2}", Errors, n, string.Join (", ", failed_fields));
 		}