## Changes
This is useful when developing the Databricks Terraform provider where
you keep a local-only build of the provider and refer to it using $HOME
from `~/.terraformrc`, for example like this:
```
plugin_cache_dir = "$HOME/.terraform.d/plugin-cache"
```
## Tests
That $HOME is passed through cannot be tested as is because the
`tfexec.Terraform` struct doesn't expose it through public fields or
methods. What can be tested is a successful run of the initialize
mutator and this is included in this commit.
## Changes
Auth relied on setting a profile. In this change we enumerate all
configuration properties and export all non-empty ones as a map with
environment variables. We then pass this map to the Terraform execution
wrapper.
This results in Terraform using the bundle's authentication
configuration.
This change is needed to make #287 work.
## Tests
Manually.
Users can opt out and use the system-installed version with the
following configuration:
```
bundle:
terraform:
exec_path: terraform
```
This will find the binary in $PATH and replace it with the found value.
If this is not set, the initialize phase will install Terraform in the
bundle's cache directory.
Pieter Noordhuis