Unable to inject different "sling" property to API due to unexported property

[migueleliasweb]

Hey guys,

I'm was playing around with https://github.com/cloudamqp/terraform-provider and trying to write some unittests and stumbled across a possible issue.

Have a look how the api variable is casted from interface{} to *.api.API:

resource_image.go

func resourceCreate(d *schema.ResourceData, meta interface{}) error {
	api := meta.(*api.API)
	keys := []string{"name", "plan", "region", "nodes"}
        #[...]
}

This would be easy to test if I could inject the api client with a fake mux to actually test the requests but the underlying code looks like this:

api/api.go

type API struct {
	sling *sling.Sling
}

func New(baseUrl, apiKey string) *API {
	return &API{
		sling: sling.New().
			Client(http.DefaultClient).
			Base(baseUrl).
			SetBasicAuth("", apiKey),
	}
}

Written this way, I seem to be unable to use a different Client when defining a custom API struct since the sling property was not exported.

Is there another way to test without injecting the sling client? If so, how can I do it?

Cheers!