As part of the 0.10 core/provider split we moved this provider, along with
all the others, out into its own repository.
In retrospect, the "terraform" provider doesn't really make sense to be
separated since it's just a thin wrapper around some core code anyway,
and so re-integrating it into core avoids the confusion that results when
Terraform Core and the terraform provider have inconsistent versions of
the backend code and dependencies.
There is no good reason to use a different version of the backend code
in the provider than in core, so this new "internal provider" mechanism
is stricter than the old one: it's not possible to use an external build
of this provider at all, and version constraints for it are rejected as
a result.
This provider is also run in-process rather than in a child process, since
again it's just a very thin wrapper around code that's already running
in Terraform core anyway, and so the process barrier between the two does
not create enough advantage to warrant the additional complexity.
This is a tough one to unit tests because the behavior is tangled up in
the code that hits releases.hashicorp.com, so we'll add this e2etest as
some extra insurance that this works end-to-end.
This e2etest runs an init, plan, apply, destroy sequence against a test
configuration using the real template and null providers downloaded from
the official repository.
This test _does_ trample a bit on the scope of some already-existing
tests, but this is mainly just to check our assumptions about how
Terraform behaves to ensure that we can reach our main conclusion here:
that the main Terraform workflow commands interact correctly with each
other in real use and we can complete the full workflow.
We already have good tests for the business logic around provider
installation, but the existing tests all stub out the main repository
server. This test completes that coverage by verifying that the installer
is able to run against the real repository and install an official release
of the template provider.
This basic test is here primarily because it's one of the few that can
run without reaching out to external services, and so it means our usual
test runs will catch situations where the main executable build is
somehow broken.
The version command itself is not very interesting to test, but it's
convenient in that its behavior is very predictable and self-contained.
Martin Atkins