fix(fail2ban, needs-restarting, rpm-updates): pad args.TEST defensively

All three plugins store their test fixtures in a multi-file layout
(one file per subprocess call, e.g. fail2ban has -ping, -status,
-status-<jail>; rpm-updates has -upgrades, -installed, -updateinfo;
needs-restarting has -reboothint, -services, -needrestart) and
splice the stderr path and the expected return code into the
lib.lftest.test() call by hand:

    lib.lftest.test([args.TEST[0] + '-ping',
                     args.TEST[1], args.TEST[2]])

That direct index access crashes with IndexError when the user
passes --test=path without trailing commas, because lib.args.csv
splits on commas and leaves a 1-element list. lib.lftest.test()
itself already pads to (stdout, stderr, retc) defensively, but
these three plugins bypass that by consuming args.TEST[1] and
args.TEST[2] before the call.

Minimal fix: pad args.TEST to 3 elements once at main() entry so
the hardcoded indices can't go out of range, and the splice into
the per-command fixture name still works unchanged.

Multi-file fixture convention stays, unlike in
strongswan-connections where it was redundant and collapsed into
a single JSON file. The three plugins here legitimately need
separate fixtures per subprocess call.

Smoke-test: running each plugin with --test=<base> (no trailing
commas) no longer crashes.

Author: markuslf

check-plugins/fail2ban/fail2ban

@@ -90,6 +90,14 @@ def main():
     except SystemExit:
         sys.exit(STATE_UNKNOWN)
 
+    # Pad args.TEST to 3 elements so the per-command fixture
+    # loads below that splice `args.TEST[1]` and `args.TEST[2]`
+    # into custom lib.lftest.test() calls do not go out of range
+    # when the user passes `--test=path` without trailing commas.
+    if args.TEST is not None:
+        while len(args.TEST) < 3:
+            args.TEST.append('')
+
     # fetch data
     # fail2ban-client ping
     if args.TEST is None:

check-plugins/needs-restarting/needs-restarting

@@ -72,6 +72,14 @@ def main():
     except SystemExit:
         sys.exit(STATE_UNKNOWN)
 
+    # Pad args.TEST to 3 elements so the per-command fixture
+    # loads below that splice `args.TEST[1]` and `args.TEST[2]`
+    # into custom lib.lftest.test() calls do not go out of range
+    # when the user passes `--test=path` without trailing commas.
+    if args.TEST is not None:
+        while len(args.TEST) < 3:
+            args.TEST.append('')
+
     # init some vars
     if args.TEST_OS_FAMILY:
         distro = {'os_family': args.TEST_OS_FAMILY}

check-plugins/rpm-updates/rpm-updates

@@ -586,6 +586,15 @@ def main():
     except SystemExit:
         sys.exit(STATE_UNKNOWN)
 
+    # Pad args.TEST to 3 elements so the `get_updates()` /
+    # `get_updateinfo()` helpers below that splice `args.TEST[1]`
+    # and `args.TEST[2]` into custom lib.lftest.test() calls do not
+    # go out of range when the user passes `--test=path` without
+    # trailing commas.
+    if args.TEST is not None:
+        while len(args.TEST) < 3:
+            args.TEST.append('')
+
     # fetch data
 
     # get the list of installed software