<!-- -*- markdown -*- -->
gc ---- Invoke git gc on your repository (Takes a repo)
=======================================================

The `gc` command is a basic pass-through to the underlying `git gc` being run
on the remote repository.  Apart from ensuring that the caller has `write`
access, to a repository which exists, no other checks are done and any spare
arguments are passed through to `git gc`.

Using `gc` in the simple case
-----------------------------

So the simple case is that a `gitano-admin` runs `gc` on a repository which
definitely exists which means they always have the rights to do so.

    SCENARIO Simple case `gc` usage

    GIVEN a standard instance
     WHEN testinstance adminkey runs gc gitano-admin
     THEN stderr is empty
      AND stdout is empty

    FINALLY the instance is torn down

We can then ensure that if the repository does not exist, we get a useful error
message back:

    SCENARIO Simple failure case `gc` usage

    GIVEN a standard instance
     WHEN testinstance adminkey, expecting failure, runs gc something
     THEN stdout is empty
      AND stderr contains repository does not exist

    FINALLY the instance is torn down

Write access checks
-------------------

A more complex case involves creating a repository to which a user has no write
permissions and trying to get that user to run `gc` on it.

    SCENARIO Write access checks for `gc` usage

    GIVEN a standard instance
      AND testinstance has keys called other
     WHEN testinstance, using adminkey, adds user other, using testinstance other
      AND testinstance adminkey runs create testrepo
      AND testinstance other, expecting failure, runs gc testrepo
     THEN stdout is empty
      AND stderr contains Ruleset denied action

    FINALLY the instance is torn down

Passing arguments to `git gc`
-----------------------------

Any spare arguments given to `gc` are passed through to `git gc` untouched.  We
can verify that arguments are passed through by passing a bad argument through
and seeing if we get an error message from the underlying `git gc` instance:

    SCENARIO Passing arguments through to `git gc`

    GIVEN a standard instance
     WHEN testinstance adminkey, expecting failure, runs gc gitano-admin --not-valid
     THEN stdout is empty

These are the `git gc` errors

      AND stderr contains error: unknown option
      AND stderr contains usage: git gc

And this demonstrates that Gitano detected the error properly

      AND stderr contains Unable to continue

    FINALLY the instance is torn down