azure.ResourceGroupExistsE returns an error if the resource group doesn't exist, rather than false

[djpnicholls]

In this function, there's a special check on the error returned by GetResourceGroupE:

terratest/modules/azure/resourcegroup.go

Lines 23 to 27 in 23563d0

	if err != nil {
	if ResourceNotFoundErrorExists(err) {
	return false, nil
	}
	return false, err

This is intended to return false if the resource group doesn't exist, since that's what ResourceGroupExistsE is checking.

However, in fact, it returns an error:

Error:      	Received unexpected error:
            	            	resources.GroupsClient#Get: Failure responding to request: StatusCode=404 -- Original Error: autorest/azure: Service returned an error. Status=404 Code="ResourceGroupNotFound" Message="Resource group 'TerraTest-C9kIU3' could not be found."

The issue is that the function ResourceNotFoundErrorExists is checking for an error with the code ResourceNotFound:

terratest/modules/azure/errors.go

Line 66 in 23563d0

return (requestError.ServiceError.Code == "ResourceNotFound")

But when checking for the existence of a resource group that doesn't exist, azure returns an error with the code ResourceGroupNotFound (as you can see in the error).

I suspect there needs to be a separate ResourceGroupNotFoundErrorExists function that can be called by ResourceGroupExistsE.