I have a simple fix for this, that checks for the presence of a config value and matches to :test, if exists. I don't seem to have privileges to contributing a fix. Will appreciate if you can either give me permissions to contributing or if you can fix this.

Here is my change:

  defp uri() do
    if config(:mix_env) && config(:mix_env) === :test do
      config :test_server_uri
    else
      @uris[config(:environment)]
    end
  end

Hi @ksakhamuri!

To contribute you can:
1.- Fork the project so you have a copy of the repo in your own account (see: https://help.github.com/articles/fork-a-repo/).
2.- Create a branch with your changes (see: https://git-scm.com/book/en/v2/Git-Branching-Basic-Branching-and-Merging).
3.- Open a pull request from that branch to the master branch of this repo. You don't need any special privileges for that since you will be uploading the changes to your own repo and I can merge them once the pull request is opened and reviewed (see: https://help.github.com/articles/using-pull-requests/).

I still haven't used exrm myself but I see your point. Thing is, your patch doesn't work because mix_env is not inside the config section of the elixir_authorizenet app, it's an environment variable.

You can however, open a pull request once you have a change that will pass the unit tests and also works in your exrm releases.

Best Regards!