feat: add tests for binary search trees

ridge-kimani · ridge-kimani · commit eb71e2ea06d3 · 2025-01-07T21:23:24.000+03:00
diff --git a/Data-Structures/Tree/BinarySearchTree.js b/Data-Structures/Tree/BinarySearchTree.js
@@ -36,13 +36,13 @@ const Node = (function Node() {
     visit(output = (value) => console.log(value)) {
       // Recursively go left
       if (this.left !== null) {
-        this.left.visit()
+        this.left.visit(output)
       }
       // Print out value
       output(this.value)
       // Recursively go right
       if (this.right !== null) {
-        this.right.visit()
+        this.right.visit(output)
       }
     }
 
@@ -116,20 +116,23 @@ const Tree = (function () {
     }
 
     // Inorder traversal
-    traverse() {
+    traverse(output = (value) => console.log(value)) {
       if (!this.root) {
         // No nodes are there in the tree till now
         return
       }
-      this.root.visit()
+      this.root.visit(output)
     }
 
     // Start by searching the root
     search(val) {
-      const found = this.root.search(val)
-      if (found !== null) {
-        return found.value
+      if (this.root) {
+        const found = this.root.search(val)
+        if (found !== null) {
+          return found.value
+        }
       }
+
       // not found
       return null
     }
diff --git a/Data-Structures/Tree/test/BinarySearchTree.test.js b/Data-Structures/Tree/test/BinarySearchTree.test.js
@@ -0,0 +1,66 @@
+import { Tree } from '../BinarySearchTree.js'
+
+describe('Binary Search Tree', () => {
+  let tree
+
+  beforeEach(() => {
+    tree = new Tree()
+    tree.addValue(10)
+    tree.addValue(5)
+    tree.addValue(15)
+    tree.addValue(3)
+    tree.addValue(8)
+  })
+
+  test('should add values to the tree', () => {
+    tree.addValue(12)
+
+    expect(tree.search(12)).toBe(12)
+    expect(tree.search(5)).toBe(5)
+    expect(tree.search(15)).toBe(15)
+  })
+
+  test('should perform in-order traversal', () => {
+    const values = []
+    const output = (val) => values.push(val)
+    tree.traverse(output)
+    expect(values).toEqual([3, 5, 8, 10, 15])
+  })
+
+  test('should remove leaf nodes correctly', () => {
+    tree.removeValue(5)
+    expect(tree.search(5)).toBeNull()
+  })
+
+  test('should remove nodes with one child correctly', () => {
+    tree.addValue(12)
+    tree.removeValue(15)
+
+    expect(tree.search(15)).toBeNull()
+    expect(tree.search(12)).toBe(12)
+  })
+
+  test('should remove nodes with two children correctly', () => {
+    tree.addValue(18)
+    tree.removeValue(15)
+
+    expect(tree.search(15)).toBeNull()
+    expect(tree.search(18)).toBe(18)
+  })
+
+  test('should return null for non-existent values', () => {
+    expect(tree.search(20)).toBeNull()
+    expect(tree.search(0)).toBeNull()
+  })
+
+  test('should handle removal of root node correctly', () => {
+    tree.removeValue(10)
+    expect(tree.search(10)).toBeNull()
+  })
+
+  test('should handle empty tree gracefully', () => {
+    const newTree = new Tree()
+    newTree.removeValue(22) // Should not throw
+    expect(newTree.search(22)).toBeNull()
+  })
+})

Original file line number	Diff line number	Diff line change
`@@ -36,13 +36,13 @@ const Node = (function Node() {`
`36`	`36`	`visit(output = (value) => console.log(value)) {`
`37`	`37`	`// Recursively go left`
`38`	`38`	`if (this.left !== null) {`
`39`		`- this.left.visit()`
	`39`	`+ this.left.visit(output)`
`40`	`40`	`}`
`41`	`41`	`// Print out value`
`42`	`42`	`output(this.value)`
`43`	`43`	`// Recursively go right`
`44`	`44`	`if (this.right !== null) {`
`45`		`- this.right.visit()`
	`45`	`+ this.right.visit(output)`
`46`	`46`	`}`
`47`	`47`	`}`
`48`	`48`
`@@ -116,20 +116,23 @@ const Tree = (function () {`
`116`	`116`	`}`
`117`	`117`
`118`	`118`	`// Inorder traversal`
`119`		`- traverse() {`
	`119`	`+ traverse(output = (value) => console.log(value)) {`
`120`	`120`	`if (!this.root) {`
`121`	`121`	`// No nodes are there in the tree till now`
`122`	`122`	`return`
`123`	`123`	`}`
`124`		`- this.root.visit()`
	`124`	`+ this.root.visit(output)`
`125`	`125`	`}`
`126`	`126`
`127`	`127`	`// Start by searching the root`
`128`	`128`	`search(val) {`
`129`		`- const found = this.root.search(val)`
`130`		`- if (found !== null) {`
`131`		`- return found.value`
	`129`	`+ if (this.root) {`
	`130`	`+ const found = this.root.search(val)`
	`131`	`+ if (found !== null) {`
	`132`	`+ return found.value`
	`133`	`+ }`
`132`	`134`	`}`
	`135`	`+`
`133`	`136`	`// not found`
`134`	`137`	`return null`
`135`	`138`	`}`