getting-started.md

Getting Started

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

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 ):

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:

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.