chore: fixing Region Tests for Forms

src/Forms/Prism.Forms.Regions/Ioc/RegionResolverOverrides.cs

@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using Prism.Navigation;
 using Prism.Navigation.Regions;
-using Prism.Navigation.Regions;
 
 namespace Prism.Ioc
 {

src/Forms/Prism.Forms.Regions/Navigation/Regions/Region.cs

@@ -282,20 +282,20 @@ private void InnerAdd(object view, string viewName, IRegionManager scopedRegionM
         {
             if (ItemMetadataCollection.FirstOrDefault(x => x.Item == view) != null)
             {
-                throw new InvalidOperationException(Resources.RegionViewExistsException);
+                throw new RegionViewException(Resources.RegionViewExistsException);
             }
 
             if (view is not VisualElement visualElement)
             {
-                throw new Exception("View is not a Visual Element");
+                throw new RegionViewException(Resources.RegionViewIsNotVisualElementException);
             }
 
             var itemMetadata = new ItemMetadata(visualElement);
             if (!string.IsNullOrEmpty(viewName))
             {
                 if (ItemMetadataCollection.FirstOrDefault(x => x.Name == viewName) != null)
                 {
-                    throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, Resources.RegionViewNameExistsException, viewName));
+                    throw new RegionViewException(string.Format(CultureInfo.InvariantCulture, Resources.RegionViewNameExistsException, viewName));
                 }
                 itemMetadata.Name = viewName;
             }

src/Forms/Prism.Forms.Regions/Properties/Resources.resx

@@ -203,6 +203,9 @@
   <data name="RegionViewExistsException" xml:space="preserve">
     <value>View already exists in region.</value>
   </data>
+  <data name="RegionViewIsNotVisualElementException" xml:space="preserve">
+    <value>View is not a Visual Element.</value>
+  </data>
   <data name="RegionViewNameExistsException" xml:space="preserve">
     <value>View with name '{0}' already exists in the region.</value>
   </data>

src/Prism.Core/Navigation/Regions/RegionViewException.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Runtime.Serialization;
+
+namespace Prism.Navigation.Regions;
+
+/// <summary>
+/// An exception when there is an issue with a View being added to a Region
+/// </summary>
+public sealed class RegionViewException : RegionException
+{
+    /// <summary>
+    /// Initializes a new <see cref="RegionViewException"/>
+    /// </summary>
+    public RegionViewException()
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new <see cref="RegionViewException"/>
+    /// </summary>
+    /// <param name="message">The Exception Message.</param>
+    public RegionViewException(string message) : base(message)
+    {
+    }
+
+    /// <inheritdoc />
+    public RegionViewException(SerializationInfo info, StreamingContext context) : base(info, context)
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new <see cref="RegionViewException"/>
+    /// </summary>
+    /// <param name="message">The Exception Message.</param>
+    /// <param name="innerException">The Inner <see cref="Exception"/>.</param>
+    public RegionViewException(string message, Exception innerException) : base(message, innerException)
+    {
+    }
+}

tests/Forms/Prism.Forms.Regions.Tests/Tests/RegionFixture.cs

@@ -94,7 +94,7 @@ public void CanAddAndRetrieveNamedViewInstance()
         [Fact]
         public void AddingDuplicateNamedViewThrows()
         {
-            var ex = Assert.Throws<InvalidOperationException>(() =>
+            var ex = Assert.Throws<RegionViewException>(() =>
             {
                 IRegion region = new Region();
 

tests/Forms/Prism.Forms.Regions.Tests/Tests/RegionNavigationServiceFixture.cs

@@ -10,6 +10,7 @@
 using Xamarin.Forms;
 using Xunit;
 using Region = Prism.Navigation.Regions.Region;
+using NuGet.Frameworks;
 
 namespace Prism.Forms.Regions.Tests
 {
@@ -1004,7 +1005,10 @@ public void WhenNavigatingWithNullCallback_ThenThrows()
             var region = new Region();
 
             var navigationUri = new Uri("/", UriKind.Relative);
-            IContainerExtension container = new Mock<IContainerExtension>().Object;
+            var containerMock = new Mock<IContainerExtension>();
+            containerMock.Setup(x => x.Resolve(typeof(IActiveRegionHelper)))
+                .Returns(new RegionResolverOverrides());
+            var container = containerMock.Object;
             var contentLoader = new Mock<RegionNavigationContentLoader>(container).Object;
             IRegionNavigationJournal journal = Mock.Of<IRegionNavigationJournal>();
 
@@ -1013,11 +1017,11 @@ public void WhenNavigatingWithNullCallback_ThenThrows()
                 Region = region
             };
 
-            ExceptionAssert.Throws<ArgumentNullException>(
-                () =>
-                {
-                    target.RequestNavigate(navigationUri);
-                });
+            Exception ex = null;
+            target.RequestNavigate(navigationUri, x => ex = x.Exception);
+
+            Assert.NotNull(ex);
+            Assert.IsType<RegionViewException>(ex);
         }
 
         [Fact]
@@ -1040,7 +1044,11 @@ public void WhenNavigatingWithNoRegionSet_ThenMarshallExceptionToCallback()
         [Fact]
         public void WhenNavigatingWithNullUri_ThenMarshallExceptionToCallback()
         {
-            IContainerExtension container = new Mock<IContainerExtension>().Object;
+
+            var containerMock = new Mock<IContainerExtension>();
+            containerMock.Setup(x => x.Resolve(typeof(IActiveRegionHelper)))
+                .Returns(new RegionResolverOverrides());
+            var container = containerMock.Object;
             var contentLoader = new Mock<RegionNavigationContentLoader>(container).Object;
             IRegionNavigationJournal journal = Mock.Of<IRegionNavigationJournal>();
 
@@ -1053,7 +1061,7 @@ public void WhenNavigatingWithNullUri_ThenMarshallExceptionToCallback()
             target.RequestNavigate("", nr => error = nr.Exception);
 
             Assert.NotNull(error);
-            Assert.IsType<ArgumentNullException>(error);
+            Assert.IsType<RegionViewException>(error);
         }