[PATCH v2 00/15] SHA-256 test fixes, part 6

This series consists mostly of additional test fixes for SHA-256, plus some test framework improvements and a new option to rev-parse.

I've opted to change the option from --object-format to --show-object-format, since I think this is more consistent with our other --show* options in rev-parse and it leaves --object-format as a possible additional option for *controlling* (not listing) the output format in the future.

Of course, opinions on this or other aspects of the series are welcome.

Changes from v1:
* Improve readability of t4011 by using helper functions.
* Change rev-parse option name to --show-object-format.

brian m. carlson (15):
  t/oid-info: allow looking up hash algorithm name
  t/oid-info: add empty tree and empty blob values
  rev-parse: add a --show-object-format option
  t1305: avoid comparing extensions
  t3429: remove SHA1 annotation
  t4010: abstract away SHA-1-specific constants
  t4011: abstract away SHA-1-specific constants
  t4015: abstract away SHA-1-specific constants
  t4027: make hash-size independent
  t4034: abstract away SHA-1-specific constants
  t4038: abstract away SHA-1 specific constants
  t4039: abstract away SHA-1-specific constants
  t4044: update test to work with SHA-256
  t4045: make hash-size independent
  t4048: abstract away SHA-1-specific constants

 Documentation/git-rev-parse.txt     |  7 +++
 builtin/rev-parse.c                 | 11 ++++
 t/oid-info/hash-info                |  9 +++
 t/t1305-config-include.sh           |  2 +-
 t/t1500-rev-parse.sh                | 15 +++++
 t/t3429-rebase-edit-todo.sh         |  2 +-
 t/t4010-diff-pathspec.sh            | 20 ++++---
 t/t4011-diff-symlink.sh             | 40 +++++++++----
 t/t4015-diff-whitespace.sh          | 89 ++++++++++++++++-----------
 t/t4027-diff-submodule.sh           | 16 ++---
 t/t4034-diff-words.sh               | 93 +++++++++++++++++------------
 t/t4038-diff-combined.sh            | 19 ++++--
 t/t4039-diff-assume-unchanged.sh    |  3 +-
 t/t4044-diff-index-unique-abbrev.sh | 46 +++++++++-----
 t/t4045-diff-relative.sh            |  2 +-
 t/t4048-diff-combined-binary.sh     | 58 ++++++++++--------
 16 files changed, 277 insertions(+), 155 deletions(-)