lambda-tester
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Unit/Integration tests for AWS Lambda handlers
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Simplifies writing unit tests for [AWS Lambda](https://aws.amazon.com/lambda/details) functions using [Node.js](https://nodejs.org).
* 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.
Complete documentation can be found in our [documentation](docs) page.
* [vandium](https://github.com/vandium-io/vandium-node) - Secures and simplifies AWS Lambda handlers
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 `feedback@vandium.io`
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.
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