S3Client.listBuckets()

import exec from 'k6/execution';

import { AWSConfig, S3Client } from 'https://jslib.k6.io/aws/0.4.0/s3.js';

const awsConfig = new AWSConfig(
  __ENV.AWS_REGION,
  __ENV.AWS_ACCESS_KEY_ID,
  __ENV.AWS_SECRET_ACCESS_KEY
);

const s3 = new S3Client(awsConfig);
const testBucketName = 'test-jslib-aws';

export default function () {
  // List the buckets the AWS authentication configuration
  // gives us access to.
  const buckets = s3.listBuckets();

  // If our test bucket does not exist, abort the execution.
  if (buckets.filter((b) => b.name === testBucketName).length == 0) {
    exec.test.abort();
  }

  // ... work with the bucket's content
}