New Engine Structure Tests (#776)

* Implement generic ItemProperty test.

* Implement ItemProperty tests.

* Seal classes.

* Add event test.

* Add basic tests for other engine types.

* Fix ItemProperty.OnMonsterHitProperties method.

* Cleanup.

* Correct test parameters.

* Set cost table value to -1.

NWN.Anvil.Tests/src/main/API/EngineStructures/EventTests.cs

@@ -0,0 +1,19 @@
+using NUnit.Framework;
+using NWN.Core;
+using Event = Anvil.API.Event;
+
+namespace Anvil.Tests.API
+{
+  [TestFixture(Category = "API.EngineStructure")]
+  public sealed class EventTests
+  {
+    [Test(Description = "Creating an event and disposing the event explicitly frees the associated memory.")]
+    public void CreateAndDisposeEventFreesNativeStructure()
+    {
+      Event nwEvent = NWScript.EventUserDefined(0xDEAD)!;
+      Assert.That(nwEvent.IsValid, Is.True, "Event was not valid after creation.");
+      nwEvent.Dispose();
+      Assert.That(nwEvent.IsValid, Is.False, "Event was still valid after disposing.");
+    }
+  }
+}

NWN.Anvil.Tests/src/main/API/EngineStructures/JsonTests.cs

@@ -0,0 +1,20 @@
+using Anvil.API;
+using NUnit.Framework;
+
+namespace Anvil.Tests.API
+{
+  [TestFixture(Category = "API.EngineStructure")]
+  public sealed class JsonTests
+  {
+    [Test(Description = "Creating a json structure and disposing it explicitly frees the associated memory.")]
+    public void CreateAndDisposeJsonFreesNativeStructure()
+    {
+      int[] test = { 1, 2 };
+      Json json = JsonUtility.ToJsonStructure(test);
+
+      Assert.That(json.IsValid, Is.True, "Json struct was not valid after creation.");
+      json.Dispose();
+      Assert.That(json.IsValid, Is.False, "Json struct was still valid after disposing.");
+    }
+  }
+}

NWN.Anvil.Tests/src/main/API/EngineStructures/LocationTests.cs

@@ -0,0 +1,18 @@
+using Anvil.API;
+using NUnit.Framework;
+
+namespace Anvil.Tests.API
+{
+  [TestFixture(Category = "API.EngineStructure")]
+  public class LocationTests
+  {
+    [Test(Description = "Creating a location and disposing the location explicitly frees the associated memory.")]
+    public void CreateAndDisposeLocationFreesNativeStructure()
+    {
+      Location location = NwModule.Instance.StartingLocation;
+      Assert.That(location.IsValid, Is.True, "Location was not valid after creation.");
+      location.Dispose();
+      Assert.That(location.IsValid, Is.False, "Location was still valid after disposing.");
+    }
+  }
+}

NWN.Anvil.Tests/src/main/API/EngineStructures/SQLQueryTests.cs

@@ -0,0 +1,18 @@
+using Anvil.API;
+using NUnit.Framework;
+
+namespace Anvil.Tests.API
+{
+  [TestFixture(Category = "API.EngineStructure")]
+  public class SQLQueryTests
+  {
+    [Test(Description = "Creating a SQL query and disposing the query explicitly frees the associated memory.")]
+    public void CreateAndDisposeSQLQueryFreesNativeStructure()
+    {
+      SQLQuery query = NwModule.Instance.PrepareSQLQuery("SELECT * FROM 'test'");
+      Assert.That(query.IsValid, Is.True, "SQL query was not valid after creation.");
+      query.Dispose();
+      Assert.That(query.IsValid, Is.False, "SQL query was still valid after disposing.");
+    }
+  }
+}

NWN.Anvil.Tests/src/main/API/EngineStructures/TalentTests.cs

@@ -0,0 +1,18 @@
+using Anvil.API;
+using NUnit.Framework;
+
+namespace Anvil.Tests.API
+{
+  [TestFixture(Category = "API.EngineStructure")]
+  public class TalentTests
+  {
+    [Test(Description = "Creating a talent and disposing the talent explicitly frees the associated memory.")]
+    public void CreateAndDisposeTalentFreesNativeStructure()
+    {
+      Talent talent = NwSkill.FromSkillType(Skill.Intimidate)!.ToTalent();
+      Assert.That(talent.IsValid, Is.True, "Talent was not valid after creation.");
+      talent.Dispose();
+      Assert.That(talent.IsValid, Is.False, "Talent was still valid after disposing.");
+    }
+  }
+}

NWN.Anvil/src/main/API/EngineStructures/ItemProperty.Create.cs

@@ -359,7 +359,10 @@ public static ItemProperty OnHitEffect(IPOnHitSaveDC saveDC, HitEffect effect)
 
     public static ItemProperty OnMonsterHitProperties(MonsterHitEffect effect)
     {
-      return NWScript.ItemPropertyOnMonsterHitProperties(effect.Property, effect.Special)!;
+      ItemProperty property = NWScript.ItemPropertyCustom((int)ItemPropertyType.OnMonsterHit, effect.Property, -1, effect.Special)!;
+      property.IntParams[2] = -1;
+
+      return property;
     }
 
     public static ItemProperty Quality(IPQuality quality)