Fix ChildrenTests test case issue

Author: Kyle-Ye

Tests/OpenAttributeGraphCompatibilityTests/Graph/SubgraphCompatibilityTests.swift

@@ -76,59 +76,56 @@ struct SubgraphCompatibilityTests {
             #expect(notifiedCount == 0)
         }
     }
-    
-    @Suite(.disabled(if: !compatibilityTestEnabled, "Subgraph children is not implemented"), .graphScope)
+
+    @MainActor
+    @Suite // Both ConditionTrait and GraphEnvironmentTrait's isRecursive are true
     struct ChildrenTests {
-        
         @Test
         func addChild() {
             let graph = Graph()
             let subgraph = Subgraph(graph: graph)
             let child = Subgraph(graph: graph)
-            
+
             subgraph.addChild(child)
             #expect(subgraph.childCount == 1)
             #expect(subgraph.isAncestor(of: child) == true)
-            
+
             #expect(subgraph.child(at: 0, tag: nil) === child)
 
             #expect(child.parentCount == 1)
             #expect(child.parent(at: 0) === subgraph)
-
-            #expect(1 == 2)
         }
-        
+
         @Test
         func addChildWithTag() {
             let graph = Graph()
             let subgraph = Subgraph(graph: graph)
             let child = Subgraph(graph: graph)
-            
+
             subgraph.addChild(child, tag: 1)
             #expect(subgraph.childCount == 1)
             #expect(subgraph.isAncestor(of: child) == true)
-            
+
             var tag = 0
             #expect(subgraph.child(at: 0, tag: &tag) === child)
             #expect(tag == 1)
-            
+
             #expect(child.parentCount == 1)
             #expect(child.parent(at: 0) === subgraph)
         }
-        
+
         @Test
         func removeChild() {
             let graph = Graph()
             let subgraph = Subgraph(graph: graph)
             let child = Subgraph(graph: graph)
-            
+
             subgraph.addChild(child)
             subgraph.removeChild(child)
             #expect(subgraph.childCount == 0)
             #expect(subgraph.isAncestor(of: child) == false)
-            
+
             #expect(child.parentCount == 0)
         }
-        
     }
 }