Add tests for trait inheritance and removals in yaml.

OpenRA.Test/OpenRA.Game/ActorInfoTest.cs

@@ -28,6 +28,10 @@ namespace OpenRA.Test
 	class MockEInfo : MockTraitInfo, Requires<MockFInfo> { }
 	class MockFInfo : MockTraitInfo, Requires<MockDInfo> { }
 
+	class MockA2Info : MockTraitInfo { }
+	class MockB2Info : MockTraitInfo { }
+	class MockC2Info : MockTraitInfo { }
+
 	[TestFixture]
 	public class ActorInfoTest
 	{
@@ -88,5 +92,65 @@ namespace OpenRA.Test
 				Assert.That(count, Is.EqualTo(Math.Floor(count)), "Should be symmetrical");
 			}
 		}
+
+		[TestCase(TestName = "Trait inheritance and removal can be composed")]
+		public void TraitInheritanceAndRemovalCanBeComposed()
+		{
+			var baseYaml = @"
+^BaseA:
+	MockA2:
+^BaseB:
+	Inherits@a: ^BaseA
+	MockB2:
+";
+			var extendedYaml = @"
+Actor:
+	Inherits@b: ^BaseB
+	-MockA2:
+";
+			var mapYaml = @"
+^BaseC:
+	MockC2:
+Actor:
+	Inherits@c: ^BaseC
+";
+
+			var actorInfo = CreateActorInfoFromYaml("Actor", mapYaml, baseYaml, extendedYaml);
+			Assert.IsFalse(actorInfo.HasTraitInfo<MockA2Info>(), "Actor should not have the MockA2 trait, but does.");
+			Assert.IsTrue(actorInfo.HasTraitInfo<MockB2Info>(), "Actor should have the MockB2 trait, but does not.");
+			Assert.IsTrue(actorInfo.HasTraitInfo<MockC2Info>(), "Actor should have the MockC2 trait, but does not.");
+		}
+
+		[TestCase(TestName = "Trait can be removed after multiple inheritance")]
+		public void TraitCanBeRemovedAfterMultipleInheritance()
+		{
+			var baseYaml = @"
+^BaseA:
+	MockA2:
+Actor:
+	Inherits: ^BaseA
+	MockA2:
+";
+			var overrideYaml = @"
+Actor:
+	-MockA2
+";
+
+			var actorInfo = CreateActorInfoFromYaml("Actor", null, baseYaml, overrideYaml);
+			Assert.IsFalse(actorInfo.HasTraitInfo<MockA2Info>(), "Actor should not have the MockA2 trait, but does.");
+		}
+
+		// This needs to match the logic used in RulesetCache.LoadYamlRules
+		ActorInfo CreateActorInfoFromYaml(string name, string mapYaml, params string[] yamls)
+		{
+			var initialNodes = mapYaml == null ? new List<MiniYamlNode>() : MiniYaml.FromString(mapYaml);
+			var yaml = yamls
+				.Select(s => MiniYaml.FromString(s))
+				.Aggregate(initialNodes, MiniYaml.MergePartial);
+			var allUnits = yaml.ToDictionary(node => node.Key, node => node.Value);
+			var unit = allUnits[name];
+			var creator = new ObjectCreator(new[] { typeof(ActorInfoTest).Assembly });
+			return new ActorInfo(creator, name, unit, allUnits);
+		}
 	}
 }