How to mock Amazon S3 in an integration test

grignaak_4931 0
Viewed 81453

I'm trying to get an "walking skeleton" of my app up that will use S3 for persistence. I would like to use a fake S3 service so each developer's desktop can read/write at will.

I thought mocks3 would be perfect, as I could get a jetty server up in my jUnit tests. The problem is that mocks3 doesn't allow any writes. Not even to set it up as far as I can tell.

So how do others do this?

integration-testing junit amazon-s3 java
7 Answers

If you're ok with depending on a running docker container, and want something well-supported, you could consider using localstack

Before running your tests, start S3 like so:

docker run --name localstack -d -p 5000:5000 -e SERVICES=s3:5000 localstack/localstack

And then stop it when tests complete like so:

docker stop localstack

You'll need to configure your S3 client to point to localhost:5000 for tests. In Java, this can be done like so:

        AmazonS3ClientBuilder.standard()
            .withEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(
                 "http://localhost:5000", 
                 "us-west-2"))
            .build();
user_29479370

Have a look at Adobe's S3Mock. This S3 Mock server can be started via a Docker container or JUnit 4/5 rules.

user_72597950
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