feat: AVLTree 100% test coverage (#1098)

Author: kho-kho-kho

Data-Structures/Tree/test/AVLTree.test.js

@@ -3,12 +3,14 @@ import { AVLTree } from '../AVLTree'
 describe('AVLTree Implementation: ', () => {
   const avlTree = new AVLTree()
   const dataList = []
-  const demoData = [1, 4, 6, 22, 7, 99, 4, 66, 77, 98]
+  const demoData = [1, 4, 6, 22, 7, 99, 4, 66, 77, 98, 87, 54, 32, 15]
 
   const avlStringTree = new AVLTree()
   const collator = new Intl.Collator()
   const stringData = ['S', 'W', 'z', 'B', 'a']
 
+  const emptyTree = new AVLTree(collator.compare)
+
   beforeAll(() => {
     demoData.forEach(item => {
       if (avlTree.add(item)) {
@@ -20,6 +22,11 @@ describe('AVLTree Implementation: ', () => {
     stringData.forEach(item => avlStringTree.add(item))
   })
 
+  it('delete and search from empty tree', () => {
+    expect(emptyTree.remove(0)).toBeFalsy()
+    expect(emptyTree.find(0)).toBeFalsy()
+  })
+
   it('checks if element is inserted properly', () => {
     expect(dataList.length).toEqual(avlTree.size)
     expect(stringData.length).toEqual(avlStringTree.size)
@@ -34,9 +41,31 @@ describe('AVLTree Implementation: ', () => {
     })
   })
 
-  it('deletes the inserted element', () => {
-    const deleteElement = dataList[3]
-    expect(avlTree.remove(deleteElement)).toBeTruthy()
-    expect(avlStringTree.remove(stringData[3])).toBeTruthy()
+  it('delete element with two valid children', () => {
+    expect(avlTree.remove(77)).toBeTruthy()
+  })
+
+  it('delete element missing L-child', () => {
+    expect(avlTree.remove(98)).toBeTruthy()
+  })
+
+  it('delete elements forcing single R-rotation', () => {
+    expect(avlTree.remove(99)).toBeTruthy()
+    expect(avlTree.remove(87)).toBeTruthy()
+  })
+
+  it('delete elements forcing R-rotation and L-rotation', () => {
+    expect(avlTree.remove(1)).toBeTruthy()
+    expect(avlTree.remove(4)).toBeTruthy()
+  })
+
+  it('delete elements forcing single L-rotation', () => {
+    expect(avlTree.remove(7)).toBeTruthy()
+    expect(avlTree.remove(15)).toBeTruthy()
+    expect(avlTree.remove(6)).toBeTruthy()
+  })
+
+  it('delete element forcing single L-rotation and R-rotation', () => {
+    expect(avlTree.remove(66)).toBeTruthy()
   })
 })