Fix CachedRepo.resolve_ref unit test for missing SHA1

CachedRepo.resolve_ref does, effectively, this:

	absref = git rev-parse --verify $ref
	git log -1 --format=format:%T $absref

Roughly, "git rev-parse" takes any ref and returns the corresponding
SHA1. If the ref looks like a SHA1 (40 hex digits), it is returned
as-is, and despite --verify is not checked for existence.

"git log" then takes the SHA1 and returns the **tree** SHA1, as
opposed to the commit one, and if the commit doesn't exist, barfs.

The unit test for resolve_ref with an invalid SHA1 currently succeeds
for the wrong reason. The mocked _rev_parse fails for an unknown SHA1
(raising cliapp.AppException), which causes resolve_ref to raise
InvalidReferenceError, which the unit test expects. However, the real
implementation of _rev_parse wouldn't fail in that way, and so the
unit test doesn't test the thing it's meant to test: that resolve_ref
actually works the expected way for an unknown SHA1. What actually
happens is that resolve_ref calls _show_tree_hash, which raises
cliapp.AppException for an unknown SHA1, resulting in horror and
despair, instead of resolve_ref raising InvalidReferenceError.

This commit fixes the unit test so that it causes the right code
path in resolve_ref to be executed. This makes the unit test suite
to fail.

0 files changed, 0 insertions, 0 deletions