* getproviders ParsePlatform: add check for invalid platform strings with too many parts
The existing logic would not catch things like a platform string containing multiple underscores. I've added an explicit check for exactly 2 parts and some basic tests to prove it.
* command/providers-lock: add tests
This commit adds some simple tests for the providers lock command. While adding this test I noticed that there was a mis-copied error message, so I replaced that with a more specific message. I also added .terraform.lock.hcl to our gitignore for hopefully obvious reasons.
getproviders.ParsePlatform: use parts in place of slice range, since it's available
* command: Providers mirror tests
The providers mirror command is already well tested in e2e tests, so this includes only the most absolutely basic test case.
This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.
If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.
