semi-weekly tests: add some help tests

after recent changes `-c help`/`-c lavc:help` crashes - create test for it

Author: MartinPulec

.github/scripts/run_scheduled_tests_data.sh

@@ -1,4 +1,6 @@
 # test cases for run_scheduled_tests.sh
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (c) 2026 CESNET, zájmové sdružení právnických osob
 #
 # For the documentation of add_test parameters see the
 # run_scheduled_tests.sh file.
@@ -10,6 +12,15 @@ add_test "-d sdl"                              should_timeout
 add_test "-t testcard -c lavc:e=libx265 -f rs -d dummy" should_timeout
 add_test "-t spout:check_lib"                  Windows_only
 
+add_test "-x help"
+add_test "-x sdp:help"
+add_test "-c help -t testcard"
+add_test "-c lavc:help -t testcard"
+add_test "-x nonexistent"                      should_fail
+add_test "-x sdp:wrongopt"                     should_fail
+add_test "-c nonexistent"                      should_fail
+add_test "-c lavc:wrongopt -t testcard"        should_fail
+
 # reflector
 add_test -v                                    run_reflector # basic sanity test
 add_test "8M 5004"                             run_reflector,should_timeout