test_cmp expected result
'
+test_expect_success 'setup submodules' '
+ test_tick &&
+ git init submod &&
+ ( cd submod && test_commit first; ) &&
+ git add submod &&
+ git commit -m first &&
+ ( cd submod && test_commit second; ) &&
+ git add submod &&
+ git commit -m second
+'
+
+test_expect_success 'diff-tree ignores trailing slash on submodule path' '
+ git diff --name-only HEAD^ HEAD submod >expect &&
+ git diff --name-only HEAD^ HEAD submod/ >actual &&
+ test_cmp expect actual
+'
+
test_done