added test suite for Question 226

Author: dmaynard24

javascript/questions-200-300/question-226/question-226.js

@@ -31,3 +31,5 @@ const invertTree = function(root) {
   }
   return root;
 };
+
+module.exports = invertTree;

javascript/questions-200-300/question-226/question-226.test.js

@@ -0,0 +1,35 @@
+const invertTree = require(`./question-226`);
+const TreeNode = require(`../../util/TreeNode`);
+
+test(`expects the result of inverting a binary tree [4, 2, 7, 1, 3, 6, 9] to be [4, 7, 2, 9, 6, 3, 1]`, () => {
+  const t7 = TreeNode(9);
+  const t6 = TreeNode(6);
+  const t5 = TreeNode(3);
+  const t4 = TreeNode(1);
+  const t3 = TreeNode(7, t6, t7);
+  const t2 = TreeNode(2, t4, t5);
+  const t1 = TreeNode(4, t2, t3);
+
+  const t3inverted = TreeNode(7, t7, t6);
+  const t2inverted = TreeNode(2, t5, t4);
+  const t1inverted = TreeNode(4, t3inverted, t2inverted);
+
+  expect(invertTree(t1)).toStrictEqual(t1inverted);
+});
+
+test(`expects the result of inverting a binary tree [2, 1, 3] to be [2, 3, 1]`, () => {
+  const t3 = TreeNode(3);
+  const t2 = TreeNode(1);
+  const t1 = TreeNode(2, t2, t3);
+
+  const t1inverted = TreeNode(2, t3, t2);
+
+  expect(invertTree(t1)).toStrictEqual(t1inverted);
+});
+
+test(`expects the result of inverting a binary tree [] to be []`, () => {
+  const t1 = TreeNode();
+  const t1inverted = TreeNode();
+
+  expect(invertTree(t1)).toStrictEqual(t1inverted);
+});

javascript/util/TreeNode.js

@@ -6,3 +6,5 @@ function TreeNode(val, left, right) {
   this.left = left === undefined ? null : left;
   this.right = right === undefined ? null : right;
 }
+
+module.exports = TreeNode;