[PATCHv2] t3306,t5304: avoid clock skew issues

[Michael J Gruber <git@drmicha.warpmail.net>]

On systems where the local time and file modification time may be out of
sync (e.g. test directory on NFS) t3306 and t5305 can fail because prune
compares times such as "now" (client time) with file modification times
(server times for remote file systems). I.e., these are spurious test
failures.

Avoid this by setting the relevant modification times to the local time.

Noticed on a system with as little as 2s time skew.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
---
I don't think we can safeguard prune itself properly. A filesystem may be out
of time sync sporadically (and produce incorrect time stamps) but then be in
sync when "git prune" is run so that we can't detect it.

v2 uses the known sha1 directly in t3306, just like the rest of the test.
---
 t/t3306-notes-prune.sh |    3 +++
 t/t5304-prune.sh       |    3 ++-
 2 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/t/t3306-notes-prune.sh b/t/t3306-notes-prune.sh
index c428217..86bf909 100755
--- a/t/t3306-notes-prune.sh
+++ b/t/t3306-notes-prune.sh
@@ -20,6 +20,9 @@ test_expect_success 'setup: create a few commits with notes' '
 	git add file3 &&
 	test_tick &&
 	git commit -m 3rd &&
+	COMMIT_FILE=.git/objects/5e/e1c35e83ea47cd3cc4f8cbee0568915fbbbd29 &&
+	test -f $COMMIT_FILE &&
+	test-chmtime =+0 $COMMIT_FILE &&
 	git notes add -m "Note #3"
 '
 
diff --git a/t/t5304-prune.sh b/t/t5304-prune.sh
index e2ed13d..d645328 100755
--- a/t/t5304-prune.sh
+++ b/t/t5304-prune.sh
@@ -14,7 +14,8 @@ add_blob() {
 	BLOB=$(echo aleph_0 | git hash-object -w --stdin) &&
 	BLOB_FILE=.git/objects/$(echo $BLOB | sed "s/^../&\//") &&
 	test $((1 + $before)) = $(git count-objects | sed "s/ .*//") &&
-	test -f $BLOB_FILE
+	test -f $BLOB_FILE &&
+	test-chmtime =+0 $BLOB_FILE
 }
 
 test_expect_success setup '
-- 
1.7.5.rc1.312.g1936c