Jonathan Sharpe textbook

Stamp Duty Land Tax

A TDD journey through a changing tax.

Step 1

In 2003, Stamp Duty Land Tax (SDLT) was introduced.

House price	Rate (%)

This is a:

✨ New feature - new behaviour has been implemented
🐛 Bug fix - existing behaviour has been made to behave
♻️ Refactor - the behaviour has not changed, just the implementation
✅ Test backfill - tests for existing behaviour were added but the behaviour itself hasn't changed
⚙️ Chore - maintenance task, behaviour and implementation haven't changed

Here is how to add Cypress E2E tests to a Create React App bootstrapped application. Assumes the *nix command line, you may need to adapt this for a Windows command line (or use WSL or Git Bash).

Install Cypress and the Testing Library utilities for it (to match the helpers CRA installs):
```
$ npm i {,@testing-library/}cypress
```
i is short for install, and the braces {} are expanded by brace expansion to cypress @testing-library/cypress.

Escaped
\|

Markup:

| Escaped |
|---|
| \| |

👩‍💻 Tester	👹 Evil Coder	👨‍🏫 Invigilator
Write a failing test	Don’t read the exercise!	No talking
Keep it simple	Make the test pass	Don't take large steps
Try to drive the code writer to the expected solution	Try to do it in a surprising way	Don't ignore bad test feedback
		No more than 3 `\|\|` or `&&`

Exercise: [Password Validator][1]
Single file test framework: [Proctor][2]

Hi here is some text this is red.

	import { render, screen } from "@testing-library/react";
	import userEvent from "@testing-library/user-event";
	import { useState } from "react";

	const App = () => {
	const [count, setCount] = useState(0);
	return (
	<div>
	<div>{count}</div>
	<button onClick={() => setCount((c) => c + 1)}>Click me!</button>

	const express = require("express");
	const request = require("supertest");

	const StatusCodes = { CREATED: 201 };
	const fakeUserData = {};

	const app = express();

	it("returns a 201 on successful signup", (done) => {
	request(app)

	FOO=123
	BAR=hello, world!