+ '3-way merge with git-read-tree -m, match H' \
+ "rm -fr [NDMALTS][NDMALTSF] Z &&
+ rm .git/index &&
+ git-read-tree $tree_A &&
+ git-checkout-index -f -u -a &&
+ git-read-tree -m $tree_O $tree_A $tree_B &&
+ check_result"
+
+: <<\END_OF_CASE_TABLE
+
+We have so far tested only empty index and clean-and-matching-A index
+case which are trivial. Make sure index requirements are also
+checked.
+
+"git-read-tree -m O A B"
+
+ O A B result index requirements
+-------------------------------------------------------------------
+ 1 missing missing missing - must not exist.
+ ------------------------------------------------------------------
+ 2 missing missing exists take B* must match B, if exists.
+ ------------------------------------------------------------------
+ 3 missing exists missing take A* must match A, if exists.
+ ------------------------------------------------------------------
+ 4 missing exists A!=B no merge must match A and be
+ up-to-date, if exists.
+ ------------------------------------------------------------------
+ 5 missing exists A==B take A must match A, if exists.
+ ------------------------------------------------------------------
+ 6 exists missing missing remove must not exist.
+ ------------------------------------------------------------------
+ 7 exists missing O!=B no merge must not exist.
+ ------------------------------------------------------------------
+ 8 exists missing O==B remove must not exist.
+ ------------------------------------------------------------------
+ 9 exists O!=A missing no merge must match A and be
+ up-to-date, if exists.
+ ------------------------------------------------------------------
+ 10 exists O==A missing remove ditto
+ ------------------------------------------------------------------
+ 11 exists O!=A O!=B no merge must match A and be
+ A!=B up-to-date, if exists.
+ ------------------------------------------------------------------
+ 12 exists O!=A O!=B take A must match A, if exists.
+ A==B
+ ------------------------------------------------------------------
+ 13 exists O!=A O==B take A must match A, if exists.
+ ------------------------------------------------------------------
+ 14 exists O==A O!=B take B if exists, must either (1)
+ match A and be up-to-date,
+ or (2) match B.
+ ------------------------------------------------------------------
+ 15 exists O==A O==B take B must match A if exists.
+ ------------------------------------------------------------------
+ 16 exists O==A O==B barf must match A if exists.
+ *multi* in one in another
+-------------------------------------------------------------------
+
+Note: we need to be careful in case 2 and 3. The tree A may contain
+DF (file) when tree B require DF to be a directory by having DF/DF
+(file).
+
+END_OF_CASE_TABLE
+
+test_expect_failure \
+ '1 - must not have an entry not in A.' \
+ "rm -f .git/index XX &&
+ echo XX >XX &&
+ git-update-index --add XX &&
+ git-read-tree -m $tree_O $tree_A $tree_B"