Running inspec aws tests through authenticated http proxy

Hi there, we're just exploring using inspec to do some testing and have hit a bit of a snag.
Our environment is pretty well locked down so any http/s traffic needs to go via a proxy. Generally we define the HTTP_PROXY environment variable and most tooling seems to work with this ok but inspec seems to be returning a "error!: 407 Proxy authentication required" response when performing a simple test (e.g. verify existence of s3 bucket). The credentials for the proxy are in the HTTP_PROXY var as user:pass@proxy:port, and indeed removing that variable gives me a "failed to open TCP Connection to" suggesting that there is no egress without the proxy setting.

Has anyone else used inspec with an authenticated proxy?

So the problem appears to be with the aws-sdk for ruby, seemingly it somehow strips the credentials out of the environment variable which causes the 407 response from the proxy.

A the moment it seems we can get round this by including the code

Aws.config[:http_proxy] = ENV['http_proxy']

in each test file.

Is there a way that I can only specify this once for a test of tests e.g. fixture_setup style?