Localstack

We use this library to help integrate localstack into our test suite.

$3

- Docker
- Docker Compose

Getting Started

First install the library:

``
npm i @firstclasspostcodes/localstack -D
`

Add the following to a jest.config.js file:

`js
module.exports = {
// starts localstack when test execution begins
globalSetup: '@firstclasspostcodes/localstack/setup',
// optional: teardown localstack after tests complete
globalTeardown: '@firstclasspostcodes/localstack/teardown',
setupFiles: ['./jest.setup.js'],
};
`

This starts & stops localstack before & after test execution. We also wait for localstack to be ready before completing the setup.

Inside jest.setup.js, you'll want to include the following:

`js
const AWS = require('aws-sdk');
const localstack = require('@firstclasspostcodes/localstack');

localstack.configureSDKInstance(AWS);

global.localstack = localstack;
`

Using global.localstack allows you easy access to the following helpers:

#### createArtifactBucket()

Creates a shared artifact bucket, useful for uploading objects into. This returns the name of the bucket.

#### uploadArtifact(filepath)

Uploads an artifact to the artifact bucket and takes care of deleting it before the process exits.

#### uploadDirectory(source)

Packages a directory as a ZIP archive and uploads it as an artifact to the artifact bucket.

#### deployLambda(source, params = {})

Takes a source directory (similar to CodeUri), archives it and creates a Lambda function.

> Note: The deployed lambda function has a wrapped handler, configuring the AWS SDK (running inside the Lambda function) to talk to localstack and not AWS. So no manual configuration of your functions is necessary.

#### invokeLambda(functionName, event = {})`

Invokes the lambda with the provided name, returning the parsed JSON response.