test_must_fail git difftool --gui --tool=test-tool --extcmd=cat
'
+test_expect_success 'difftool --rotate-to' '
+ difftool_test_setup &&
+ test_when_finished git reset --hard &&
+ echo 1 >1 &&
+ echo 2 >2 &&
+ echo 4 >4 &&
+ git add 1 2 4 &&
+ git commit -a -m "124" &&
+ git difftool --no-prompt --extcmd=cat --rotate-to="2" HEAD^ >output&&
+ cat >expect <<-\EOF &&
+ 2
+ 4
+ 1
+ EOF
+ test_cmp output expect
+'
+
+test_expect_success 'difftool --skip-to' '
+ difftool_test_setup &&
+ test_when_finished git reset --hard &&
+ git difftool --no-prompt --extcmd=cat --skip-to="2" HEAD^ >output &&
+ cat >expect <<-\EOF &&
+ 2
+ 4
+ EOF
+ test_cmp output expect
+'
+
+test_expect_success 'difftool --rotate/skip-to error condition' '
+ test_must_fail git difftool --no-prompt --extcmd=cat --rotate-to="3" HEAD^ &&
+ test_must_fail git difftool --no-prompt --extcmd=cat --skip-to="3" HEAD^
+'
test_done