https://github.com/vandium-io/lambda-tester

Helper for unit testing AWS Lambda functions
https://github.com/vandium-io/lambda-tester

aws-lambda

Last synced: 3 days ago
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Helper for unit testing AWS Lambda functions

• Host: GitHub
• URL: https://github.com/vandium-io/lambda-tester
• Owner: vandium-io
• License: bsd-3-clause
• Created: 2016-03-22T20:02:26.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2024-02-07T16:08:19.000Z (11 months ago)
• Last Synced: 2024-05-22T08:01:44.095Z (8 months ago)
• Topics: aws-lambda
• Language: JavaScript
• Size: 305 KB
• Stars: 269
• Watchers: 13
• Forks: 51
• Open Issues: 25
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md

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# lambda-tester

Simplifies writing unit tests for [AWS Lambda](https://aws.amazon.com/lambda/details) functions using [Node.js](https://nodejs.org).

## Features

* Verifies correct handler behavior

* Mocks event types with code

* Works asynchronously

* Supports Promises

* Verifies Node.js runtime version

* AWS X-Ray support [experimental]

* Detects resource leaks [experimental]

* Easily integrates with test frameworks (Mocha and Jasmine)

* Handlers can be loaded and removed after execution

* Lightweight and won't impact performance

* Maps the environment variable `LAMBDA_TASK_ROOT` to the application's root

* Automatically loads .env files

* Works with Node 10.x, and 12.x

## Installation

Install via npm.

	npm install lambda-tester --save-dev

## Getting Started

Lambda handlers with support for callbacks use the typical Node.js asynchronous signature:

```js

exports.handler = function( event, context, callback ) {

    callback( null, 'success!' );

}

```

The following example shows a simple case for validating that the Lambda (handler) was called successfully (i.e. `callback( null, result )`:

```js

const LambdaTester = require( 'lambda-tester' );

const myHandler = require( '../index' ).handler;

describe( 'handler', function() {

	it( 'test success', async function() {

		await LambdaTester( myHandler )

			.event( { name: 'Fred' } )

			.expectResult();

	});

});

```

If the handler calls `callback( err )`, then the test will fail.

Additionally, if one wanted to test for failure, then the following code would be used:

```js

const LambdaTester = require( 'lambda-tester' );

const myHandler = require( '../index' ).handler;

describe( 'handler', function() {

	it( 'test failure', async function() {

		await LambdaTester( myHandler )

			.event( { name: 'Unknown' } )

			.expectError();

	});

});

```

**Note:** you must either return the `LambdaTester` instance back to the testing

framework or use the `await`/`async` keywords.

## Documentation

Complete documentation can be found in our [documentation](docs) page.

## Projects Using `lambda-tester`

* [vandium](https://github.com/vandium-io/vandium-node) - Secures and simplifies AWS Lambda handlers

## Feedback

We'd love to get feedback on how you're using lambda-tester and things we could add to make this tool better. Feel free to contact us at `[email protected]`

## Compatibility

Starting with version 4.0, lambda-tester supports node versions 10 and higher. If you require support for older versions of node, then use a previous version of lambda-tester.

## License

[BSD-3-Clause](https://en.wikipedia.org/wiki/BSD_licenses)