tests/sched_change_priority: add test app

tests/sched_change_priority/Makefile

@@ -0,0 +1,13 @@
+include ../Makefile.tests_common
+
+USEMODULE += nice
+USEMODULE += ps
+USEMODULE += shell
+USEMODULE += shell_commands
+
+# Use a terminal that does not introduce extra characters into the stream.
+RIOT_TERMINAL ?= socat
+
+APP_SHELL_FMT ?= NONE
+
+include $(RIOTBASE)/Makefile.include

tests/sched_change_priority/Makefile.ci

@@ -0,0 +1,9 @@
+BOARD_INSUFFICIENT_MEMORY := \
+    arduino-duemilanove \
+    arduino-leonardo \
+    arduino-nano \
+    arduino-uno \
+    atmega328p \
+    atmega328p-xplained-mini \
+    nucleo-l011k4 \
+    #

tests/sched_change_priority/main.c

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2019 Otto-von-Guericke-Universität Magdeburg
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     tests
+ * @{
+ *
+ * @file
+ * @brief       Test application for sched_change_priority / nice
+ *
+ * @author      Marian Buschsieweke <marian.buschsieweke@ovgu.de>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "architecture.h"
+#include "sched.h"
+#include "shell.h"
+#include "shell_commands.h"
+#include "thread.h"
+
+static int sc_hint(int argc, char **argv);
+
+static WORD_ALIGNED char t2_stack[THREAD_STACKSIZE_TINY];
+static WORD_ALIGNED char t3_stack[THREAD_STACKSIZE_DEFAULT];
+static kernel_pid_t t3_pid;
+
+static const shell_command_t cmds[] = {
+    { "hint", "Display the correct invocation of nice for this teset", sc_hint },
+    { NULL, NULL, NULL }
+};
+
+/*
+ * Note: An extra shell command just for displaying this hint is very much of
+ *       an overkill for a human being, especially since the ps command already
+ *       provides all the details. However, for automatic testing this makes it
+ *       easy to extract the pid of t3 and the numeric value of
+ *       THREAD_PRIORITY_MAIN - 1, resulting in more robust automatic testing.
+ *       A shell command also has the convenient side effect of synchronizing
+ *       with the shell.
+ */
+static int sc_hint(int argc, char **argv)
+{
+    (void)argc;
+    (void)argv;
+
+    printf("Run \"nice %" PRIkernel_pid " %u\"\n",
+           t3_pid, (unsigned)THREAD_PRIORITY_MAIN - 1);
+
+    return EXIT_SUCCESS;
+}
+
+static void *t2_func(void *unused)
+{
+    (void)unused;
+
+    while (1) {
+        /* blocking t3 from running with busy loop while t3 has lower prio than me */
+    }
+
+    return NULL;
+}
+
+static void *t3_func(void *unused)
+{
+    (void)unused;
+
+    while (1) {
+        uint8_t prio = THREAD_PRIORITY_MAIN + 2;
+        printf("[t3] Setting my priority to THREAD_PRIORITY_MAIN + 2 = %u\n",
+               (unsigned)prio);
+        sched_change_priority(thread_get_active(), prio);
+        puts("[t3] Running again.");
+    }
+
+    return NULL;
+}
+
+int main(void)
+{
+    thread_create(t2_stack, sizeof(t2_stack), THREAD_PRIORITY_MAIN + 1,
+                  THREAD_CREATE_STACKTEST, t2_func, NULL, "t2");
+
+    t3_pid = thread_create(t3_stack, sizeof(t3_stack), THREAD_PRIORITY_MAIN - 1,
+                           THREAD_CREATE_STACKTEST, t3_func, NULL, "t3");
+
+    puts("[main] Use shell command \"nice\" to increase prio of t3.\n"
+         "[main] If it works, it will run again. The \"hint\" cmd can be useful.");
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(cmds, line_buf, SHELL_DEFAULT_BUFSIZE);
+
+    return 0;
+}

tests/sched_change_priority/tests/01-run.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+
+import sys
+from testrunner import run
+
+
+def testfunc(child):
+    child.sendline("hint")
+    child.expect(r"Run \"nice (\d+) (\d+)\"\r\n")
+    pid = int(child.match.group(1))
+    prio = int(child.match.group(2))
+    child.sendline(f"nice {pid} {prio}")
+    child.expect_exact('[t3] Running again.')
+
+
+if __name__ == "__main__":
+    sys.exit(run(testfunc))