t7610-mergetool: use test_cmp instead of test $(cat file) = $txt

diff --git a/t/t0090-cache-tree.sh b/t/t0090-cache-tree.sh
index 94fcb4a78e661ae793eef54ae98b4821218b1e29..504334e552251ed0c1f74536f6fd09ffccda615d 100755 (executable)
--- a/t/t0090-cache-tree.sh
+++ b/t/t0090-cache-tree.sh
@@ -261,13 +261,16 @@ test_expect_success 'no phantom error when switching trees' '
 '
 
 test_expect_success 'switching trees does not invalidate shared index' '
-       git update-index --split-index &&
-       >split &&
-       git add split &&
-       test-tool dump-split-index .git/index | grep -v ^own >before &&
-       git commit -m "as-is" &&
-       test-tool dump-split-index .git/index | grep -v ^own >after &&
-       test_cmp before after
+       (
+               sane_unset GIT_TEST_SPLIT_INDEX &&
+               git update-index --split-index &&
+               >split &&
+               git add split &&
+               test-tool dump-split-index .git/index | grep -v ^own >before &&
+               git commit -m "as-is" &&
+               test-tool dump-split-index .git/index | grep -v ^own >after &&
+               test_cmp before after
+       )
 '
 
 test_done