[PATCH 2/2] selftests: gpio: expect gpio-mockup to reject a range with no lines

[Danish Khateeb <danishkhateeb03@gmail.com>]

Since commit 446e8c31d0fc ("gpio: mockup: reject invalid
gpio_mockup_ranges widths"), gpio-mockup refuses to load when a range
has no lines. The "no lines defined" case of gpio-mockup.sh still
expects gpio_mockup_ranges=0,0 to load and create no chip, so the test
now fails there:

  # 2.  Module load error tests
  # 2.1 no lines defined
  # test failed: insert gpio-mockup failed with error 1
  # GPIO gpio-mockup test FAIL

Check that the module rejects that range instead.

Fixes: 446e8c31d0fc ("gpio: mockup: reject invalid gpio_mockup_ranges widths")
Assisted-by: LLM
Signed-off-by: Danish Khateeb <danishkhateeb03@gmail.com>
---

Notes:
    Tested on v7.3-rc5 (x86_64, KASAN and lockdep, virtme-ng):
    - before: gpio-mockup.sh fails at 2.1, both by default and with -f.
    - after: it passes by default, with -f, and with -t cdev_v1 and
      -f -t cdev_v1 (on a GPIO_CDEV_V1=y kernel).
    - control: with "-1,32" in place of "0,0", the new check fails with
      "insert gpio-mockup with ranges <-1,32> did not fail".

 tools/testing/selftests/gpio/gpio-mockup.sh | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/gpio/gpio-mockup.sh b/tools/testing/selftests/gpio/gpio-mockup.sh
index fc2dd4c24d06..41c8a1c1502e 100755
--- a/tools/testing/selftests/gpio/gpio-mockup.sh
+++ b/tools/testing/selftests/gpio/gpio-mockup.sh
@@ -310,6 +310,16 @@ insmod_test()
 	remove_module || fail "failed to remove module with error $?"
 }
 
+# Load the module with the given ranges and check that it is rejected.
+insmod_fail_test()
+{
+	local ranges=$1
+
+	if modprobe -q $module "gpio_mockup_ranges=$ranges"; then
+		fail "insert $module with ranges <$ranges> did not fail"
+	fi
+}
+
 while getopts ":frvt:" opt; do
 	case $opt in
 	f)
@@ -378,7 +388,7 @@ if [ "$full_test" ]; then
 fi
 echo "2.  Module load error tests"
 echo "2.1 no lines defined"
-insmod_test "0,0"
+insmod_fail_test "0,0"
 if [ "$full_test" ]; then
 	echo "2.2 ignore range overlap"
 	insmod_test "0,32,0,1" 32
-- 
2.55.0