Bucket names in s3 must be globally unique (meaning only 1 user can create a bucket named "test"). It's most likely that somebody has already created the "test" bucket.
I suggest prefixing your bucket names with some identifier that you can expect to have a reasonable likelihood of uniqueness.
An example might be:
http://docs.aws.amazon.com/AmazonS3/latest/gsg/CreatingABucket.html (See section 3)
Why are S3 and Google Storage bucket names a global namespace?