From d153c6c668e6f3f57ee99f089dec21e0c4c67eb5 Mon Sep 17 00:00:00 2001
From: Kaspar Arme <kaspar.arme@reach-u.com>
Date: Wed, 9 Oct 2019 09:10:22 +0300
Subject: [PATCH] Add unit tests to postfix expression evaluation function.
 Resolves #34
---
 .../postfix-expression-evaluation/index.js &#124; 8 ++-
 .../postfix-expression-evaluation.test.js &#124; 55 +++++++++++++++++++
 2 files changed, 61 insertions(+), 2 deletions(-)
 create mode 100644 src/_DataStructures_/Stack/postfix-expression-evaluation/postfix-expression-evaluation.test.js
diff --git a/src/_DataStructures_/Stack/postfix-expression-evaluation/index.js b/src/_DataStructures_/Stack/postfix-expression-evaluation/index.js
index 3441abb5..9db393e9 100644
--- a/src/_DataStructures_/Stack/postfix-expression-evaluation/index.js
+++ b/src/_DataStructures_/Stack/postfix-expression-evaluation/index.js
@@ -15,9 +15,9 @@ function evaluatePostfixExpression(expression) {
 s.push(Number(char));
 } else {
 // if char is an operator then pop two elements from stack, evaluate them accordingly based on operator.
- //push the result to stack 
+ //push the result to stack
 let val1 = s.pop();
- let val2 = s.pop()
+ let val2 = s.pop();
 switch (char) {
 case '+':
 s.push(val2 + val1);
@@ -38,3 +38,7 @@ function evaluatePostfixExpression(expression) {
 //pop the value of postfix expression
 return s.pop();
 }
+
+module.exports = {
+ evaluatePostfixExpression,
+};
diff --git a/src/_DataStructures_/Stack/postfix-expression-evaluation/postfix-expression-evaluation.test.js b/src/_DataStructures_/Stack/postfix-expression-evaluation/postfix-expression-evaluation.test.js
new file mode 100644
index 00000000..47e0de42
--- /dev/null
+++ b/src/_DataStructures_/Stack/postfix-expression-evaluation/postfix-expression-evaluation.test.js
@@ -0,0 +1,55 @@
+const { evaluatePostfixExpression } = require('.');
+
+describe('Postfix expression evaluation', function () {
+ it('should be a function', function () {
+ expect(typeof evaluatePostfixExpression).toEqual('function');
+ });
+ 
+ it('should return a number', function () {
+ const expression = '11+';
+ 
+ expect(typeof evaluatePostfixExpression(expression)).toEqual('number')
+ });
+ 
+ it('should handle addition', function () {
+ const expression = '23+';
+ const expected = 5;
+ 
+ expect(evaluatePostfixExpression(expression)).toEqual(expected);
+ });
+ 
+ it('should handle subtraction', function () {
+ const expression = '54-';
+ const expected = 1;
+ 
+ expect(evaluatePostfixExpression(expression)).toEqual(expected);
+ });
+ 
+ it('should handle multiplication', function () {
+ const expression = '34*';
+ const expected = 12;
+ 
+ expect(evaluatePostfixExpression(expression)).toEqual(expected);
+ });
+ 
+ it('should handle division', function () {
+ const expression = '62/';
+ const expected = 3;
+ 
+ expect(evaluatePostfixExpression(expression)).toEqual(expected);
+ });
+ 
+ it('should handle negative numbers', function () {
+ const expression = '25-';
+ const expected = -3;
+ 
+ expect(evaluatePostfixExpression(expression)).toEqual(expected);
+ });
+ 
+ it('should handle multiple operators', function () {
+ const expression = '123*+';
+ const expected = 7;
+ 
+ expect(evaluatePostfixExpression(expression)).toEqual(expected);
+ });
+});
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