[PATCH] Add tests for diff-tree

This adds and reorganizes some tests for diff-tree

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 332 insertions, 170 deletions

diff --git a/t/lib-read-tree-m-3way.sh b/t/lib-read-tree-m-3way.sh
new file mode 100644
index 000000000..d920c6b3a
--- /dev/null
+++ b/t/lib-read-tree-m-3way.sh
@@ -0,0 +1,144 @@
+: Included from t1000-read-tree-m-3way.sh and others
+# Original tree.
+mkdir Z
+for a in N D M
+do
+    for b in N D M
+    do
+        p=$a$b
+	echo This is $p from the original tree. >$p
+	echo This is Z/$p from the original tree. >Z/$p
+	test_expect_success \
+	    "adding test file $p and Z/$p" \
+	    'git-update-cache --add $p &&
+	    git-update-cache --add Z/$p'
+    done
+done
+echo This is SS from the original tree. >SS
+test_expect_success \
+    'adding test file SS' \
+    'git-update-cache --add SS'
+cat >TT <<\EOF
+This is a trivial merge sample text.
+Branch A is expected to upcase this word, here.
+There are some filler lines to avoid diff context
+conflicts here,
+like this one,
+and this one,
+and this one is yet another one of them.
+At the very end, here comes another line, that is
+the word, expected to be upcased by Branch B.
+This concludes the trivial merge sample file.
+EOF
+test_expect_success \
+    'adding test file TT' \
+    'git-update-cache --add TT'
+test_expect_success \
+    'prepare initial tree' \
+    'tree_O=$(git-write-tree)'
+
+################################################################
+# Branch A and B makes the changes according to the above matrix.
+
+################################################################
+# Branch A
+
+to_remove=$(echo D? Z/D?)
+rm -f $to_remove
+test_expect_success \
+    'change in branch A (removal)' \
+    'git-update-cache --remove $to_remove'
+
+for p in M? Z/M?
+do
+    echo This is modified $p in the branch A. >$p
+    test_expect_success \
+	'change in branch A (modification)' \
+        "git-update-cache $p"
+done
+
+for p in AN AA Z/AN Z/AA
+do
+    echo This is added $p in the branch A. >$p
+    test_expect_success \
+	'change in branch A (addition)' \
+	"git-update-cache --add $p"
+done
+
+echo This is SS from the modified tree. >SS
+echo This is LL from the modified tree. >LL
+test_expect_success \
+    'change in branch A (addition)' \
+    'git-update-cache --add LL &&
+     git-update-cache SS'
+mv TT TT-
+sed -e '/Branch A/s/word/WORD/g' <TT- >TT
+rm -f TT-
+test_expect_success \
+    'change in branch A (edit)' \
+    'git-update-cache TT'
+
+mkdir DF
+echo Branch A makes a file at DF/DF, creating a directory DF. >DF/DF
+test_expect_success \
+    'change in branch A (change file to directory)' \
+    'git-update-cache --add DF/DF'
+
+test_expect_success \
+    'recording branch A tree' \
+    'tree_A=$(git-write-tree)'
+	   
+################################################################
+# Branch B
+# Start from O
+
+rm -rf [NDMASLT][NDMASLT] Z DF
+mkdir Z
+test_expect_success \
+    'reading original tree and checking out' \
+    'git-read-tree $tree_O &&
+     git-checkout-cache -a'
+
+to_remove=$(echo ?D Z/?D)
+rm -f $to_remove
+test_expect_success \
+    'change in branch B (removal)' \
+    "git-update-cache --remove $to_remove"
+
+for p in ?M Z/?M
+do
+    echo This is modified $p in the branch B. >$p
+    test_expect_success \
+	'change in branch B (modification)' \
+	"git-update-cache $p"
+done
+
+for p in NA AA Z/NA Z/AA
+do
+    echo This is added $p in the branch B. >$p
+    test_expect_success \
+	'change in branch B (addition)' \
+	"git-update-cache --add $p"
+done
+echo This is SS from the modified tree. >SS
+echo This is LL from the modified tree. >LL
+test_expect_success \
+    'change in branch B (addition and modification)' \
+    'git-update-cache --add LL &&
+     git-update-cache SS'
+mv TT TT-
+sed -e '/Branch B/s/word/WORD/g' <TT- >TT
+rm -f TT-
+test_expect_success \
+    'change in branch B (modification)' \
+    'git-update-cache TT'
+
+echo Branch B makes a file at DF. >DF
+test_expect_success \
+    'change in branch B (addition of a file to conflict with directory)' \
+    'git-update-cache --add DF'
+
+test_expect_success \
+    'recording branch B tree' \
+    'tree_B=$(git-write-tree)'
+
diff --git a/t/t1000-read-tree-m-3way.sh b/t/t1000-read-tree-m-3way.sh
index d7f900969..bd7406fd5 100755
--- a/t/t1000-read-tree-m-3way.sh
+++ b/t/t1000-read-tree-m-3way.sh
@@ -71,177 +71,8 @@ In addition:
  DF: a special case, where A makes a directory and B makes a file.
 
 '
-
 . ./test-lib.sh
-
-# Original tree.
-mkdir Z
-for a in N D M
-do
-    for b in N D M
-    do
-        p=$a$b
-	echo This is $p from the original tree. >$p
-	echo This is Z/$p from the original tree. >Z/$p
-	test_expect_success \
-	    "adding test file $p and Z/$p" \
-	    'git-update-cache --add $p &&
-	    git-update-cache --add Z/$p'
-    done
-done
-echo This is SS from the original tree. >SS
-test_expect_success \
-    'adding test file SS' \
-    'git-update-cache --add SS'
-cat >TT <<\EOF
-This is a trivial merge sample text.
-Branch A is expected to upcase this word, here.
-There are some filler lines to avoid diff context
-conflicts here,
-like this one,
-and this one,
-and this one is yet another one of them.
-At the very end, here comes another line, that is
-the word, expected to be upcased by Branch B.
-This concludes the trivial merge sample file.
-EOF
-test_expect_success \
-    'adding test file TT' \
-    'git-update-cache --add TT'
-test_expect_success \
-    'prepare initial tree' \
-    'tree_O=$(git-write-tree)'
-
-test_expect_success \
-    'commit initial tree' \
-    'commit_O=$(echo "Original tree for the merge test." |
-     git-commit-tree $tree_O)'
-echo $commit_O >.git/HEAD-O
-
-################################################################
-# Branch A and B makes the changes according to the above matrix.
-
-################################################################
-# Branch A
-
-to_remove=$(echo D? Z/D?)
-rm -f $to_remove
-test_expect_success \
-    'change in branch A (removal)' \
-    'git-update-cache --remove $to_remove'
-
-for p in M? Z/M?
-do
-    echo This is modified $p in the branch A. >$p
-    test_expect_success \
-	'change in branch A (modification)' \
-        "git-update-cache $p"
-done
-
-for p in AN AA Z/AN Z/AA
-do
-    echo This is added $p in the branch A. >$p
-    test_expect_success \
-	'change in branch A (addition)' \
-	"git-update-cache --add $p"
-done
-
-echo This is SS from the modified tree. >SS
-echo This is LL from the modified tree. >LL
-test_expect_success \
-    'change in branch A (addition)' \
-    'git-update-cache --add LL &&
-     git-update-cache SS'
-mv TT TT-
-sed -e '/Branch A/s/word/WORD/g' <TT- >TT
-rm -f TT-
-test_expect_success \
-    'change in branch A (edit)' \
-    'git-update-cache TT'
-
-mkdir DF
-echo Branch A makes a file at DF/DF, creating a directory DF. >DF/DF
-test_expect_success \
-    'change in branch A (change file to directory)' \
-    'git-update-cache --add DF/DF'
-
-test_expect_success \
-    'recording branch A tree' \
-    'tree_A=$(git-write-tree)'
-test_expect_success \
-    'committing branch A changes' \
-    'commit_A=$(echo "Branch A for the merge test." |
-           git-commit-tree $tree_A -p $commit_O)'
-echo $commit_A >.git/HEAD-A
-	   
-################################################################
-# Branch B
-# Start from O
-
-rm -rf [NDMASLT][NDMASLT] Z DF
-mkdir Z
-test_expect_success \
-    'reading original tree and checking out' \
-    'git-read-tree $tree_O &&
-     git-checkout-cache -a'
-
-to_remove=$(echo ?D Z/?D)
-rm -f $to_remove
-test_expect_success \
-    'change in branch B (removal)' \
-    "git-update-cache --remove $to_remove"
-
-for p in ?M Z/?M
-do
-    echo This is modified $p in the branch B. >$p
-    test_expect_success \
-	'change in branch B (modification)' \
-	"git-update-cache $p"
-done
-
-for p in NA AA Z/NA Z/AA
-do
-    echo This is added $p in the branch B. >$p
-    test_expect_success \
-	'change in branch B (addition)' \
-	"git-update-cache --add $p"
-done
-echo This is SS from the modified tree. >SS
-echo This is LL from the modified tree. >LL
-test_expect_success \
-    'change in branch B (addition and modification)' \
-    'git-update-cache --add LL &&
-     git-update-cache SS'
-mv TT TT-
-sed -e '/Branch B/s/word/WORD/g' <TT- >TT
-rm -f TT-
-test_expect_success \
-    'change in branch B (modification)' \
-    'git-update-cache TT'
-
-echo Branch B makes a file at DF. >DF
-test_expect_success \
-    'change in branch B (addition of a file to conflict with directory)' \
-    'git-update-cache --add DF'
-
-test_expect_success \
-    'recording branch B tree' \
-    'tree_B=$(git-write-tree)'
-test_expect_success \
-    'committing branch B changes' \
-    'commit_B=$(echo "Branch B for the merge test." |
-           git-commit-tree $tree_B -p $commit_O)'
-echo $commit_B >.git/HEAD-B
-
-################################################################
-# Done preparation.
-
-test_debug '
-    for T in O A B
-    do
-	echo "# $T $(eval git-cat-file commit \$commit_$T | sed -e 1q)"
-    done
-'
+. ../lib-read-tree-m-3way.sh
 
 ################################################################
 # Try merging and showing the various diffs
diff --git a/t/t4002-diff-basic.sh b/t/t4002-diff-basic.sh
new file mode 100644
index 000000000..1bfbc2043
--- /dev/null
+++ b/t/t4002-diff-basic.sh
@@ -0,0 +1,187 @@
+#!/bin/sh
+#
+# Copyright (c) 2005 Junio C Hamano
+#
+
+test_description='Test diff raw-output.
+
+'
+. ./test-lib.sh
+. ../lib-read-tree-m-3way.sh
+
+cat >.test-plain-OA <<\EOF
++100644 blob ccba72ad3888a3520b39efcf780b9ee64167535d AA
++100644 blob 7e426fb079479fd67f6d81f984e4ec649a44bc25 AN
+-100644 blob bcc68ef997017466d5c9094bcf7692295f588c9a DD
++040000 tree 6d50f65d3bdab91c63444294d38f08aeff328e42 DF
+-100644 blob 141c1f1642328e4bc46a7d801a71da392e66791e DM
+-100644 blob 35abde1506ddf806572ff4d407bd06885d0f8ee9 DN
++100644 blob 1d41122ebdd7a640f29d3c9cc4f9d70094374762 LL
+*100644->100644 blob 03f24c8c4700babccfd28b654e7e8eac402ad6cd->103d9f89b50b9aad03054b579be5e7aa665f2d57 MD
+*100644->100644 blob b258508afb7ceb449981bd9d63d2d3e971bf8d34->b431b272d829ff3aa4d1a5085f4394ab4d3305b6 MM
+*100644->100644 blob bd084b0c27c7b6cc34f11d6d0509a29be3caf970->a716d58de4a570e0038f5c307bd8db34daea021f MN
+*100644->100644 blob 40c959f984c8b89a2b02520d17f00d717f024397->2ac547ae9614a00d1b28275de608131f7a0e259f SS
+*100644->100644 blob 4ac13458899ab908ef3b1128fa378daefc88d356->4c86f9a85fbc5e6804ee2e17a797538fbe785bca TT
+*040000->040000 tree 7d670fdcdb9929f6c7dac196ff78689cd1c566a1->5e5f22072bb39f6e12cf663a57cb634c76eefb49 Z
+EOF
+
+cat >.test-recursive-OA <<\EOF
++100644 blob ccba72ad3888a3520b39efcf780b9ee64167535d AA
++100644 blob 7e426fb079479fd67f6d81f984e4ec649a44bc25 AN
+-100644 blob bcc68ef997017466d5c9094bcf7692295f588c9a DD
++100644 blob 68a6d8b91da11045cf4aa3a5ab9f2a781c701249 DF/DF
+-100644 blob 141c1f1642328e4bc46a7d801a71da392e66791e DM
+-100644 blob 35abde1506ddf806572ff4d407bd06885d0f8ee9 DN
++100644 blob 1d41122ebdd7a640f29d3c9cc4f9d70094374762 LL
+*100644->100644 blob 03f24c8c4700babccfd28b654e7e8eac402ad6cd->103d9f89b50b9aad03054b579be5e7aa665f2d57 MD
+*100644->100644 blob b258508afb7ceb449981bd9d63d2d3e971bf8d34->b431b272d829ff3aa4d1a5085f4394ab4d3305b6 MM
+*100644->100644 blob bd084b0c27c7b6cc34f11d6d0509a29be3caf970->a716d58de4a570e0038f5c307bd8db34daea021f MN
+*100644->100644 blob 40c959f984c8b89a2b02520d17f00d717f024397->2ac547ae9614a00d1b28275de608131f7a0e259f SS
+*100644->100644 blob 4ac13458899ab908ef3b1128fa378daefc88d356->4c86f9a85fbc5e6804ee2e17a797538fbe785bca TT
++100644 blob 8acb8e9750e3f644bf323fcf3d338849db106c77 Z/AA
++100644 blob 087494262084cefee7ed484d20c8dc0580791272 Z/AN
+-100644 blob 879007efae624d2b1307214b24a956f0a8d686a8 Z/DD
+-100644 blob 9b541b2275c06e3a7b13f28badf5294e2ae63df4 Z/DM
+-100644 blob beb5d38c55283d280685ea21a0e50cfcc0ca064a Z/DN
+*100644->100644 blob d41fda41b7ec4de46b43cb7ea42a45001ae393d5->a79ac3be9377639e1c7d1edf1ae1b3a5f0ccd8a9 Z/MD
+*100644->100644 blob 4ca22bae2527d3d9e1676498a0fba3b355bd1278->61422ba9c2c873416061a88cd40a59a35b576474 Z/MM
+*100644->100644 blob b16d7b25b869f2beb124efa53467d8a1550ad694->a5c544c21cfcb07eb80a4d89a5b7d1570002edfd Z/MN
+EOF
+cat >.test-plain-OB <<\EOF
++100644 blob 6aa2b5335b16431a0ef71e5c0a28be69183cf6a2 AA
+-100644 blob bcc68ef997017466d5c9094bcf7692295f588c9a DD
++100644 blob 71420ab81e254145d26d6fc0cddee64c1acd4787 DF
+*100644->100644 blob 141c1f1642328e4bc46a7d801a71da392e66791e->3c4d8de5fbad08572bab8e10eef8dbb264cf0231 DM
++100644 blob 1d41122ebdd7a640f29d3c9cc4f9d70094374762 LL
+-100644 blob 03f24c8c4700babccfd28b654e7e8eac402ad6cd MD
+*100644->100644 blob b258508afb7ceb449981bd9d63d2d3e971bf8d34->19989d4559aae417fedee240ccf2ba315ea4dc2b MM
++100644 blob 15885881ea69115351c09b38371f0348a3fb8c67 NA
+-100644 blob a4e179e4291e5536a5e1c82e091052772d2c5a93 ND
+*100644->100644 blob c8f25781e8f1792e3e40b74225e20553041b5226->cdb9a8c3da571502ac30225e9c17beccb8387983 NM
+*100644->100644 blob 40c959f984c8b89a2b02520d17f00d717f024397->2ac547ae9614a00d1b28275de608131f7a0e259f SS
+*100644->100644 blob 4ac13458899ab908ef3b1128fa378daefc88d356->c4e4a12231b9fa79a0053cb6077fcb21bb5b135a TT
+*040000->040000 tree 7d670fdcdb9929f6c7dac196ff78689cd1c566a1->1ba523955d5160681af65cb776411f574c1e8155 Z
+EOF
+cat >.test-recursive-OB <<\EOF
++100644 blob 6aa2b5335b16431a0ef71e5c0a28be69183cf6a2 AA
+-100644 blob bcc68ef997017466d5c9094bcf7692295f588c9a DD
++100644 blob 71420ab81e254145d26d6fc0cddee64c1acd4787 DF
+*100644->100644 blob 141c1f1642328e4bc46a7d801a71da392e66791e->3c4d8de5fbad08572bab8e10eef8dbb264cf0231 DM
++100644 blob 1d41122ebdd7a640f29d3c9cc4f9d70094374762 LL
+-100644 blob 03f24c8c4700babccfd28b654e7e8eac402ad6cd MD
+*100644->100644 blob b258508afb7ceb449981bd9d63d2d3e971bf8d34->19989d4559aae417fedee240ccf2ba315ea4dc2b MM
++100644 blob 15885881ea69115351c09b38371f0348a3fb8c67 NA
+-100644 blob a4e179e4291e5536a5e1c82e091052772d2c5a93 ND
+*100644->100644 blob c8f25781e8f1792e3e40b74225e20553041b5226->cdb9a8c3da571502ac30225e9c17beccb8387983 NM
+*100644->100644 blob 40c959f984c8b89a2b02520d17f00d717f024397->2ac547ae9614a00d1b28275de608131f7a0e259f SS
+*100644->100644 blob 4ac13458899ab908ef3b1128fa378daefc88d356->c4e4a12231b9fa79a0053cb6077fcb21bb5b135a TT
++100644 blob 6c0b99286d0bce551ac4a7b3dff8b706edff3715 Z/AA
+-100644 blob 879007efae624d2b1307214b24a956f0a8d686a8 Z/DD
+*100644->100644 blob 9b541b2275c06e3a7b13f28badf5294e2ae63df4->d77371d15817fcaa57eeec27f770c505ba974ec1 Z/DM
+-100644 blob d41fda41b7ec4de46b43cb7ea42a45001ae393d5 Z/MD
+*100644->100644 blob 4ca22bae2527d3d9e1676498a0fba3b355bd1278->697aad7715a1e7306ca76290a3dd4208fbaeddfa Z/MM
++100644 blob d12979c22fff69c59ca9409e7a8fe3ee25eaee80 Z/NA
+-100644 blob a18393c636b98e9bd7296b8b437ea4992b72440c Z/ND
+*100644->100644 blob 3fdbe17fd013303a2e981e1ca1c6cd6e72789087->7e09d6a3a14bd630913e8c75693cea32157b606d Z/NM
+EOF
+cat >.test-plain-AB <<\EOF
+*100644->100644 blob ccba72ad3888a3520b39efcf780b9ee64167535d->6aa2b5335b16431a0ef71e5c0a28be69183cf6a2 AA
+-100644 blob 7e426fb079479fd67f6d81f984e4ec649a44bc25 AN
++100644 blob 71420ab81e254145d26d6fc0cddee64c1acd4787 DF
+-040000 tree 6d50f65d3bdab91c63444294d38f08aeff328e42 DF
++100644 blob 3c4d8de5fbad08572bab8e10eef8dbb264cf0231 DM
++100644 blob 35abde1506ddf806572ff4d407bd06885d0f8ee9 DN
+-100644 blob 103d9f89b50b9aad03054b579be5e7aa665f2d57 MD
+*100644->100644 blob b431b272d829ff3aa4d1a5085f4394ab4d3305b6->19989d4559aae417fedee240ccf2ba315ea4dc2b MM
+*100644->100644 blob a716d58de4a570e0038f5c307bd8db34daea021f->bd084b0c27c7b6cc34f11d6d0509a29be3caf970 MN
++100644 blob 15885881ea69115351c09b38371f0348a3fb8c67 NA
+-100644 blob a4e179e4291e5536a5e1c82e091052772d2c5a93 ND
+*100644->100644 blob c8f25781e8f1792e3e40b74225e20553041b5226->cdb9a8c3da571502ac30225e9c17beccb8387983 NM
+*100644->100644 blob 4c86f9a85fbc5e6804ee2e17a797538fbe785bca->c4e4a12231b9fa79a0053cb6077fcb21bb5b135a TT
+*040000->040000 tree 5e5f22072bb39f6e12cf663a57cb634c76eefb49->1ba523955d5160681af65cb776411f574c1e8155 Z
+EOF
+cat >.test-recursive-AB <<\EOF
+*100644->100644 blob ccba72ad3888a3520b39efcf780b9ee64167535d->6aa2b5335b16431a0ef71e5c0a28be69183cf6a2 AA
+-100644 blob 7e426fb079479fd67f6d81f984e4ec649a44bc25 AN
++100644 blob 71420ab81e254145d26d6fc0cddee64c1acd4787 DF
+-100644 blob 68a6d8b91da11045cf4aa3a5ab9f2a781c701249 DF/DF
++100644 blob 3c4d8de5fbad08572bab8e10eef8dbb264cf0231 DM
++100644 blob 35abde1506ddf806572ff4d407bd06885d0f8ee9 DN
+-100644 blob 103d9f89b50b9aad03054b579be5e7aa665f2d57 MD
+*100644->100644 blob b431b272d829ff3aa4d1a5085f4394ab4d3305b6->19989d4559aae417fedee240ccf2ba315ea4dc2b MM
+*100644->100644 blob a716d58de4a570e0038f5c307bd8db34daea021f->bd084b0c27c7b6cc34f11d6d0509a29be3caf970 MN
++100644 blob 15885881ea69115351c09b38371f0348a3fb8c67 NA
+-100644 blob a4e179e4291e5536a5e1c82e091052772d2c5a93 ND
+*100644->100644 blob c8f25781e8f1792e3e40b74225e20553041b5226->cdb9a8c3da571502ac30225e9c17beccb8387983 NM
+*100644->100644 blob 4c86f9a85fbc5e6804ee2e17a797538fbe785bca->c4e4a12231b9fa79a0053cb6077fcb21bb5b135a TT
+*100644->100644 blob 8acb8e9750e3f644bf323fcf3d338849db106c77->6c0b99286d0bce551ac4a7b3dff8b706edff3715 Z/AA
+-100644 blob 087494262084cefee7ed484d20c8dc0580791272 Z/AN
++100644 blob d77371d15817fcaa57eeec27f770c505ba974ec1 Z/DM
++100644 blob beb5d38c55283d280685ea21a0e50cfcc0ca064a Z/DN
+-100644 blob a79ac3be9377639e1c7d1edf1ae1b3a5f0ccd8a9 Z/MD
+*100644->100644 blob 61422ba9c2c873416061a88cd40a59a35b576474->697aad7715a1e7306ca76290a3dd4208fbaeddfa Z/MM
+*100644->100644 blob a5c544c21cfcb07eb80a4d89a5b7d1570002edfd->b16d7b25b869f2beb124efa53467d8a1550ad694 Z/MN
++100644 blob d12979c22fff69c59ca9409e7a8fe3ee25eaee80 Z/NA
+-100644 blob a18393c636b98e9bd7296b8b437ea4992b72440c Z/ND
+*100644->100644 blob 3fdbe17fd013303a2e981e1ca1c6cd6e72789087->7e09d6a3a14bd630913e8c75693cea32157b606d Z/NM
+EOF
+
+test_expect_success \
+    'diff-tree of known trees.' \
+    'git-diff-tree $tree_O $tree_A >.test-a &&
+     cmp -s .test-a .test-plain-OA'
+
+test_expect_success \
+    'diff-tree of known trees.' \
+    'git-diff-tree -r $tree_O $tree_A >.test-a &&
+     cmp -s .test-a .test-recursive-OA'
+
+test_expect_success \
+    'diff-tree of known trees.' \
+    'git-diff-tree $tree_O $tree_B >.test-a &&
+     cmp -s .test-a .test-plain-OB'
+
+test_expect_success \
+    'diff-tree of known trees.' \
+    'git-diff-tree -r $tree_O $tree_B >.test-a &&
+     cmp -s .test-a .test-recursive-OB'
+
+test_expect_success \
+    'diff-tree of known trees.' \
+    'git-diff-tree $tree_A $tree_B >.test-a &&
+     cmp -s .test-a .test-plain-AB'
+
+test_expect_success \
+    'diff-tree of known trees.' \
+    'git-diff-tree -r $tree_A $tree_B >.test-a &&
+     cmp -s .test-a .test-recursive-AB'
+
+################################################################
+# Now we have established the baseline, we do not have to
+# rely on individual object ID values that much.
+
+test_expect_success \
+    'diff-tree O A == diff-tree -R A O' \
+    'git-diff-tree $tree_O $tree_A >.test-a &&
+    git-diff-tree -R $tree_A $tree_O >.test-b &&
+    cmp -s .test-a .test-b'
+
+test_expect_success \
+    'diff-tree -r O A == diff-tree -r -R A O' \
+    'git-diff-tree -r $tree_O $tree_A >.test-a &&
+    git-diff-tree -r -R $tree_A $tree_O >.test-b &&
+    cmp -s .test-a .test-b'
+
+test_expect_success \
+    'diff-tree B A == diff-tree -R A B' \
+    'git-diff-tree $tree_B $tree_A >.test-a &&
+    git-diff-tree -R $tree_A $tree_B >.test-b &&
+    cmp -s .test-a .test-b'
+
+test_expect_success \
+    'diff-tree -r B A == diff-tree -r -R A B' \
+    'git-diff-tree -r $tree_B $tree_A >.test-a &&
+    git-diff-tree -r -R $tree_A $tree_B >.test-b &&
+    cmp -s .test-a .test-b'
+
+test_done