public Bucket getBucket( String bucketName ) throws SdkClientException {
    return s3Client.doesBucketExistV2( bucketName ) ? new Bucket( bucketName ) : null;
  }
@Test public void testGetBucketNotFound_ReturnsNull() throws Exception {
    Bucket actual = provider.getBucket( UNKNOWN_BUCKET );
    assertNull( actual );
  }