tests/gnrc_rpl_srh: run unittests through shell

Using the shell to run unittests allows not needing
to wait for a string at the start of the test which
makes the test independent having the application reset
after the terminal is open.

tests/gnrc_rpl_srh/main.c

@@ -234,11 +234,6 @@ static int _ipreg(int argc, char **argv)
     return 0;
 }
 
-static const shell_command_t shell_commands[] = {
-    { "ip", "Registers pktdump to protocol number 59 (no next header)", _ipreg },
-    { NULL, NULL, NULL }
-};
-
 static void run_unittests(void)
 {
     EMB_UNIT_TESTFIXTURES(fixtures) {
@@ -255,9 +250,23 @@ static void run_unittests(void)
     TESTS_END();
 }
 
-int main(void)
+static int _unittests(int argc, char** argv)
 {
+    (void) argc;
+    (void) argv;
+
     run_unittests();
+    return 0;
+}
+
+static const shell_command_t shell_commands[] = {
+    { "ip", "Registers pktdump to protocol number 59 (no next header)", _ipreg },
+    { "unittests", "Runs unitest", _unittests},
+    { NULL, NULL, NULL }
+};
+
+int main(void)
+{
     shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
     return 0;
 }

tests/gnrc_rpl_srh/tests/01-run.py

@@ -337,7 +337,7 @@ def test_time_exc(child, iface, hw_dst, ll_dst, ll_src):
 def testfunc(child):
     global sniffer
     tap = get_bridge(os.environ["TAP"])
-
+    child.sendline("unittests")
     child.expect(r"OK \((\d+) tests\)")     # wait for and check result of unittests
     print("." * int(child.match.group(1)), end="", flush=True)
     lladdr_src = get_host_lladdr(tap)