Mocking S3 in Node.js using Sinon

index.js

var Aws = require('aws-sdk');
var sinon = require('sinon');

// Only works for 'createBucket', 'update' and a few others since most API methods are generated dynamically
// upon instantiation. Very counterintuitive, thanks Amazon!
var createBucket = sinon.stub(Aws.S3.prototype, 'createBucket');
createBucket.yields(null, 'Me create bucket');

// For other methods, we can 'assign' the stubs to the proto, already defined function won't be overridden
var listBuckets = Aws.S3.prototype.listBuckets = sinon.stub();
listBuckets.yields(null, 'Me list buckets');

var s3 = new Aws.S3();
s3.createBucket({Bucket: 'my-bucket'}, function(err, arg1) {
    console.log(arg1);
});
s3.listBuckets(function(err, arg1) {
    console.log(arg1);
});

console.log('Called #createBucket() ' + s3.createBucket.callCount + ' time(s)');
console.log('Called #listBuckets() ' + s3.listBuckets.callCount + ' time(s)');

package.json

{
  "name": "node-s3-stub",
  "version": "0.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "BSD",
  "dependencies": {
    "sinon": "~1.14.1",
    "aws-sdk": "~2.1.17"
  }
}

For putObject:

const putObjectStub = AWS.S3.prototype.putObject = sinon.stub();
putObjectStub.yields(null, 'data');

You guys are lifesavers. All of the sudden aws-sdk-mock stopped mocking and I couldn't trace the cause (plus, deps on that library are outdated and there have been no commits in about half a year).

I should have just been doing this all along.

@joerx thank you

Thanks for your help.

does it work with getObjects and listObjects?

Thanks @joerx

Thanks, this helped me to write my unit tests

hello how can i write testcase for uploading to s3, and create bucket in nodejs

Nice. Great example. It works me for listObjectsV2 also. I think it will support all.

Nice. Great example. It works me for listObjectsV2 also. I think it will support all.

Hi, Can you please share you code for mocking listObjectsV2?

Thank you @joerx 😄

thanks a lot

how to create such stub for s3.upload and how to restore them ?

const putObjectStub = AWS.S3.prototype.putObject = sinon.stub();
putObjectStub.yields(null, 'data');

const uplaodStub = (AWS.S3.prototype.upload= sinon.stub());
uplaod.yields(null, 'data');

Thanks