## 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.
Pieter Noordhuis