fix: fix addChild: addChild: is not in sync with its implementation

Author: AhmedHamdiy

src/Containers-AVL-Tree-Tests/CTAVLTreeTest.class.st

@@ -340,3 +340,19 @@ CTAVLTreeTest >> testSizeOneElement [
 	tree add: 42.
 	self assert: tree size equals: 1
 ]
+
+{ #category : 'tests' }
+CTAVLTreeTest >> testChildParentRelationship [
+	tree add: 50.
+	tree add: 30.
+	tree add: 70.
+	
+	self assert: (tree root left parent) equals: tree root.
+	self assert: (tree root right parent) equals: tree root
+]
+
+{ #category : 'tests' }
+CTAVLTreeTest >> testRootHasNoParent [
+	tree add: 14.
+	self assert: tree root parent isNil
+]

src/Containers-AVL-Tree/CTAVLAbstractNode.class.st

@@ -15,6 +15,9 @@ Date: October 20, 2023
 Class {
 	#name : 'CTAVLAbstractNode',
 	#superclass : 'Object',
+	#instVars : [
+		'parent'
+	],
 	#category : 'Containers-AVL-Tree',
 	#package : 'Containers-AVL-Tree'
 }
@@ -72,4 +75,14 @@ CTAVLAbstractNode >> remove: anObject path: list [
 { #category : 'accessing' }
 CTAVLAbstractNode >> withAllChildren: aCollection [ 
 	"Default is to do nothing"
+]
+
+{ #category : 'accessing' }
+CTAVLAbstractNode >> parent [
+	^ parent
+]
+
+{ #category : 'accessing' }
+CTAVLAbstractNode >> parent: aNode [
+	parent := aNode
 ]

src/Containers-AVL-Tree/CTAVLNilNode.class.st

@@ -15,7 +15,7 @@ Class {
 
 { #category : 'adding' }
 CTAVLNilNode >> addChild: newObject [
-	^ CTAVLNode with: newObject
+	^ self parent replace: self with: (CTAVLNode with: newObject)
 ]
 
 { #category : 'private' }

src/Containers-AVL-Tree/CTAVLNode.class.st

@@ -180,7 +180,8 @@ CTAVLNode >> left [
 
 { #category : 'accessing' }
 CTAVLNode >> left: aNode [ 
-	left := aNode
+	left := aNode.
+	aNode parent: self
 ]
 
 { #category : 'private' }
@@ -261,8 +262,9 @@ CTAVLNode >> right [
 ]
 
 { #category : 'accessing' }
-CTAVLNode >> right: anObject [ 
-	right := anObject
+CTAVLNode >> right: aNode [ 
+	right := aNode.
+	aNode parent: self 
 ]
 
 { #category : 'private' }

src/Containers-AVL-Tree/CTAVLTree.class.st

@@ -99,3 +99,8 @@ CTAVLTree >> search: anInteger [
 CTAVLTree >> size [
 	^ root nodeSize
 ]
+
+{ #category : 'accessing' }
+CTAVLTree >> root [
+	^ root
+]