[PATCH] Additional git-rev-list unit tests to demonstrate problems that require fixes

1. --merge-order doesn't deal properly with a specified head that has no parent

* FAIL 11: head has no parent

2. --merge-order doesn't deal properly with arguments of the form
head ^head

* FAIL 30: head ^head --merge-order git-rev-list --merge-order
--show-breaks a3 ^a3

3. if one of the specified heads is reachable from the other, the
head gets printed twice and this causes problems for upcoming
versions of gitk. This is true for both --merge-order and non
--merge-order style of invocations.
* FAIL 24: one specified head reachable from another a4, c3, --merge-order
* FAIL 26: one specified head reachable from another a4, c3, no --merge-order
* FAIL 27: one specified head reachable from another c3, a4, no --merge-order

4. --merge-order aborts with commits that list the same parent twice...it should handle it more gracefully.
* no longer unit testable

5. broken interaction between --merge-order and --max-age
previously posted as:

"[PATCH 1/2] Test case that demonstrates problem with --merge-order, --max-age interaction"
* FAIL 23: --max-age=c3, --merge-order

Later patches in this patch set fix these problems.

Signed-off-by: Jon Seymour <jon.seymour@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>