---
title: "String Calculator"
url: "https://osherove.com/string-calculator.md"
canonical: "https://osherove.com/string-calculator"
tags: []
author: "Roy Osherove"
description: "Intro The following is a TDD Kata- an exercise in coding, refactoring and test-first, that you should apply daily for at least 15 minutes . You can downloa"
usage: "Licensed under CC BY 4.0 — reuse, quote and adapt with attribution (Roy Osherove, link to the original page)."
license: "https://creativecommons.org/licenses/by/4.0/"
---

# String Calculator

TDD Kata

# Intro

The following is a TDD Kata- an exercise in coding, refactoring and test-first, that you should apply daily for at least 15 minutes .

[You can download a more readable version of the Kata here.](https://osherove.com/s/String-Calculator-Kata-v1.pdf)

## Before you start: 

- Try not to read ahead.

- Do one task at a time. The trick is to learn to work incrementally.

- Make sure you only test for **correct inputs**. there is no need to test for invalid inputs for this kata

---

# Step 1

```
Create a simple String calculator with a method signature:
```

```
Hints:
```

---

# Detail 3

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---

## About the author

**Roy Osherove**: Senior Solutions Architect at AWS working on AI for production and AI-driven development; author of The Art of Unit Testing and Elastic Leadership, with about 20 years of consulting and training on unit testing, TDD, team leadership and continuous delivery.

### Sites

- [RobotPaper](https://robotpaper.ai/): This blog: AI patterns and anti-patterns, AI and coding agents, and engineering leadership.
- [osherove.com](https://osherove.com): Roy's personal site. Author of The Art of Unit Testing and Elastic Leadership; consulting and training on unit testing, TDD, team leadership and continuous delivery, plus about 20 years of blog posts.
- [The Art of Unit Testing](https://www.artofunittesting.com): The Art of Unit Testing, 3rd Edition (Manning): readable, maintainable, trustworthy unit tests, plus TDD workshops in C#, JavaScript, Java and Kotlin.
- [5whys.com](https://www.5whys.com): Roy's writing on software team leadership: self-organizing teams, surviving chaos, learning mode and the Elastic Leadership model.
- [Pipeline Driven](https://pipelinedriven.org): Continuous delivery and DevOps practices: build patterns, pipeline-friendly testing, DevOps metrics and enterprise DevOps.
- [Elastic Leadership](https://www.elasticleadership.com): Elastic Leadership, Roy's framework for software team leaders (survival, learning and self-organizing modes).

### Social

- X: https://x.com/royosherove
- LinkedIn: https://www.linkedin.com/in/osherove/

### Contact

- Contact form: https://forms.gle/jQSx5KoXvrVA1JCK7

### License

Licensed under CC BY 4.0 — reuse, quote and adapt with attribution (Roy Osherove, link to the original page). License: https://creativecommons.org/licenses/by/4.0/