https://github.com/dsomleff/ibm-tdd-badge
JS TDD Katas
https://github.com/dsomleff/ibm-tdd-badge
javascript jest jest-tests js tdd tdd-javascript tdd-kata
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JS TDD Katas
- Host: GitHub
- URL: https://github.com/dsomleff/ibm-tdd-badge
- Owner: dsomleff
- Created: 2021-04-06T11:55:55.000Z (about 5 years ago)
- Default Branch: master
- Last Pushed: 2021-04-06T12:36:27.000Z (about 5 years ago)
- Last Synced: 2025-10-21T22:33:20.838Z (8 months ago)
- Topics: javascript, jest, jest-tests, js, tdd, tdd-javascript, tdd-kata
- Language: JavaScript
- Homepage:
- Size: 52.7 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Cloud Garage TDD
Summary of tasks for obtaining the [Test-Driven Development](https://www.ibm.com/cloud/architecture/content/course/test-driven-development) badge.
This repo contains solutions for katas represented in course.
Down below is text from origin repo for course.
# Set up project
0. Clone this git repository
* In your profile > settings > SSH Keys confirm you have set up an SSH Key for Github. If not, then set up SSH access to github. [Connecting to GitHub with SSH](https://help.github.com/enterprise/2.6/user/articles/connecting-to-github-with-ssh/)
1. Install Node.js (v8.1.4 or above)
* Mac/Linux: Install nvm from https://github.com/creationix/nvm, then run `nvm use` from your terminal
* Windows: Download and install Node.js from https://nodejs.org/en/download/
2. From your terminal, run `npm init -y`
# Install Jest
**Jest** is a JavaScript test framework that we can use for testing both front-end and back-end code.
One of Jest's philosophies is to provide an integrated "zero-configuration" experience for writing tests.
Conveniently, this means that it includes everything you need for TDD in a single package (test runner, assertions,
matchers, spies, stubs and mocks)
The jest documentation can be found here: https://jestjs.io/docs/en/getting-started
1. Install jest with `npm install --save-dev jest`
2. Modify your `package.json` file, replacing:
```
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
```
with
```
"scripts": {
"test": "jest --verbose",
"tdd": "jest --verbose --watch --onlyChanged"
},
```
3. Run `npm test`
This command runs all tests and exits. Typically, we will call this from within the build pipeline.
4. Run `npm run tdd`
This command continuously watches files for changes and rerun tests related to changed files.
This is the command we will be using most often during TDD.
# Configure pre-commit hooks [Optional]
To prevent bad commits, we can configure pre-commit hooks to ensure that unit tests are run before every commit.
1. Install husky with `npm install --save-dev husky`
2. Modify your `package.json` file, replacing:
```
"scripts": {
"test": "jest --verbose",
"tdd": "jest --verbose --watch --onlyChanged"
},
```
with
```
"scripts": {
"test": "jest --verbose",
"tdd": "jest --verbose --watch --onlyChanged",
"precommit": "npm test"
},
```
# Configure your IDE [Optional]
## IntelliJ
In Preferences:
1. Under Language & Frameworks > JavaScript, set your JavaScript language version to "ECMAScript 6".
2. Under Language & Frameworks > JavaScript > Libraries, download and enable both `jest` and `node`.
# Explore the canary test
Open up `server/00-canary/canary.spec.js`, and note that:
1. For jest to find your tests, you need to place your tests in a `__tests__` folder,
or name your test files with a `.spec.js` or `.test.js` extension.
2. `describe` creates a block that groups together several related tests in one "test suite".
You can also nest `describe` blocks if you have a hierarchy of tests.
3. `it` takes two arguments. The first argument describes the test; the second argument is a function
that contains the expectations to test.
4. When you're writing tests, you often need to check that values meet certain conditions.
`expect` gives you access to a number of "matchers" that let you validate different things.
A good introduction to the available matchers can be found here: https://facebook.github.io/jest/docs/en/using-matchers.html
5. Together, the descriptions that we use in the `describe` and `it` blocks are shown in the test output.
The aim is to structure and name our tests in such a way that the test output reads like a "requirements spec".
# Let's get started!
Now that you're all set, let's get started with the TDD exercises.
As you go through the TDD exercises, keep in mind the **Four Rules of Simple Design**,
and the **Transformation Priority Premise**.
## [The Four Rules of Simple Design](https://martinfowler.com/bliki/BeckDesignRules.html):
* **_Passes the tests_**
* **_Reveals intention_**
* **_No duplication_**
* **_Fewest elements_**
## [The Transformation Priority Premise](https://8thlight.com/blog/uncle-bob/2013/05/27/TheTransformationPriorityPremise.html):
```
(01) [{} –> nil] no code => return nil
(02) [nil->constant] nil => simple constant
(03) [constant->constant+] simple constant => complex constant
(04) [constant->scalar] complex constant => variable or an argument
(05) [statement->statements] adding more unconditional statements.
(06) [unconditional->if] splitting the execution path
(07) [scalar->array]
(08) [array->container]
(09) [statement->recursion]
(10) [if->while]
(11) [expression->function] replacing an expression with a function or algorithm
(12) [variable->assignment] replacing the value of a variable.
```
## [Simplified Transformation Priority Premise](https://8thlight.com/blog/micah-martin/2012/11/17/transformation-priority-premise-applied.html):
```
(01) constant => a value
(02) scalar => a local binding, or variable
(03) invocation => calling a function/method
(04) conditional => if/switch/case/cond
(05) while loop => applies to for loops as well
(06) assignment => replacing the value of a variable
```