Mock AWS

Mocking AWS API calls

Use either mockService to mock an entire service, or mockMethod to mock just a single method. Both take the AWS service class (e.g. what you get from import S3 from 'aws-sdk/clients/s3') and the method names/name you want mocked. Optionally you can set the specific API version you want, it will default to the latest.

The resulting methods are sinon.spys. You can use them in the usual way in your spec/test assertions. The method also has a property request. This is a sinon.stub. Use it as usual to specify the return value. If you want your test to be asynchronous and pause on the method call then use a Promise as the return value and resolve it later.

The methods will also validate the passed parameters against the 'schema' AWS has catching errors early.

import S3 from 'aws-sdk/clients/s3'
import { mockService } from '@mindhive/mock-aws'

const s3 = mockService(S3, ['getObject', 'putObject'])
s3.getObject.request.withArgs(sinon.match({ Key: expectedKey }))
  .returnsValue({ Body: image })
const result = await s3.getObject(params).promise()
s3.getObject.should.have.been.calledOnce

Testing against DynamoDB

This package installs a bin script dynamodb-local to start a local DynamoDB. The first time this will download and install the AWS local DynamoDB under: /node_modules/dynamodb-localhost/dynamodb/bin.

Then in your test code:

import dynamodbDriver from '@mindhive/mock-aws/dynamodb-driver'
import DynamoDb from 'aws-sdk/clients/dynamodb'

await dynamodbDriver.createTable({
  TableName: 'Users',
  ...
}).promise()
  
const docClient = new DynamoDb.DocumentClient({ service: dynamodbDriver })