Introduce ability to map Uri fields

**Visual Studio**'s code analysis (rightly) complains that our view models are not of type `Uri`, despite ending in `Url`. Fair. Our `TopicMappingService`, however, doesn't support mapping to type `Uri`. So we've introduced that functionality—alongside some extensions of tests to ensure that they're working correctly.

Author: JeremyCaney

OnTopic.Tests/TopicMappingServiceTest.cs

@@ -182,12 +182,14 @@ public async Task MapNullablePropertiesWithInvalidValues() {
       topic.Attributes.SetValue("NullableInteger", "A");
       topic.Attributes.SetValue("NullableBoolean", "43");
       topic.Attributes.SetValue("NullableDateTime", "Hello World");
+      topic.Attributes.SetValue("NullableUrl", "invalid://Web\\Path\\File!?@Query=String?");
 
       var target                = await mappingService.MapAsync<NullablePropertyTopicViewModel>(topic).ConfigureAwait(false);
 
       Assert.IsNull(target.NullableInteger);
       Assert.IsNull(target.NullableBoolean);
       Assert.IsNull(target.NullableDateTime);
+      Assert.IsNull(target.NullableUrl);
 
       //The following should not be null since they map to non-nullable properties which will have default values
       Assert.AreEqual(topic.Title, target.Title);
@@ -214,6 +216,7 @@ public async Task MapNullablePropertiesWithValidValues() {
       topic.Attributes.SetValue("NullableDouble", "3.14159265359");
       topic.Attributes.SetValue("NullableBoolean", "tRuE");
       topic.Attributes.SetValue("NullableDateTime", "10/15/1976");
+      topic.Attributes.SetValue("NullableUrl", "/Web/Path/File?Query=String");
 
       topic.Attributes.SetValue("Title", "Hello World.");
       topic.Attributes.SetValue("IsHidden", "true");
@@ -226,6 +229,7 @@ public async Task MapNullablePropertiesWithValidValues() {
       Assert.AreEqual<double?>(3.14159265359, target.NullableDouble);
       Assert.AreEqual<bool?>(true, target.NullableBoolean);
       Assert.AreEqual<DateTime?>(new DateTime(1976, 10, 15), target.NullableDateTime);
+      Assert.AreEqual<Uri?>(new Uri("/Web/Path/File?Query=String", UriKind.RelativeOrAbsolute), target.NullableUrl);
 
       Assert.AreEqual<string?>(topic.Title, target.Title);
       Assert.AreEqual<bool?>(target.IsHidden, target.IsHidden);

OnTopic.Tests/ViewModels/NullablePropertyTopicViewModel.cs

@@ -28,11 +28,14 @@ public class NullablePropertyTopicViewModel {
 
     public DateTime? NullableDateTime { get; set; }
 
+    public Uri? NullableUrl { get; set; }
+
     public String? Title { get; set; }
 
     public bool? IsHidden { get; set; }
 
     public DateTime? LastModified { get; set; }
 
+
   } //Class
 } //Namespace

OnTopic/Internal/Reflection/TypeMemberInfoCollection.cs

@@ -41,7 +41,8 @@ static TypeMemberInfoCollection() {
         typeof(double?),
         typeof(string),
         typeof(DateTime),
-        typeof(DateTime?)
+        typeof(DateTime?),
+        typeof(Uri)
       };
     }
 
@@ -434,6 +435,11 @@ private static bool IsSettableType(Type sourceType, Type? targetType = null) {
           valueObject = date;
         }
       }
+      else if (type.Equals(typeof(Uri))) {
+        if (Uri.TryCreate(value, UriKind.RelativeOrAbsolute, out var uri)) {
+          valueObject = uri;
+        }
+      }
 
       return valueObject;