public class SomeTest {

    @Rule
    public LocalStackContainer localstack = new LocalStackContainer()
            .withServices(S3);
    
    @Test
    public void someTestMethod() {
        AmazonS3 s3 = AmazonS3ClientBuilder
                        .standard()
                        .withEndpointConfiguration(localstack.getEndpointConfiguration(S3))
                        .withCredentials(localstack.getDefaultCredentialsProvider())
                        .build();
        
                s3.createBucket("foo");
                s3.putObject("foo", "bar", "baz");