Add test if the message queue is fair

tests/test_queue_fairness/Makefile

@@ -0,0 +1,6 @@
+PROJECT = test_queue_fairness
+include ../Makefile.tests_common
+
+USEMODULE += vtimer
+
+include $(RIOTBASE)/Makefile.include

tests/test_queue_fairness/main.c

@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @ingroup tests
+ * @{
+ * @file
+ * @brief    Test if the queue used for messaging is fair.
+ * @author   René Kijewski <rene.kijewski@fu-berlin.de>
+ * @}
+ */
+
+#include <stdio.h>
+
+#include "flags.h"
+#include "kernel.h"
+#include "msg.h"
+#include "sched.h"
+#include "thread.h"
+#include "vtimer.h"
+
+#define STACK_SIZE (KERNEL_CONF_STACKSIZE_DEFAULT + KERNEL_CONF_STACKSIZE_PRINTF)
+
+#define NUM_CHILDREN (3)
+#define NUM_ITERATIONS (10)
+
+static char stacks[NUM_CHILDREN][STACK_SIZE];
+static int pids[NUM_CHILDREN];
+static char names[NUM_CHILDREN][8];
+
+static int parent_pid;
+
+static void child_fun(void)
+{
+    printf("Start of %s.\n", active_thread->name);
+
+    for (int i = 0; i < NUM_ITERATIONS; ++i) {
+        msg_t m;
+        m.type = i + 1;
+        m.content.ptr = (void *) active_thread->name;
+        msg_send(&m, parent_pid, true);
+    }
+
+    printf("End of %s.\n", active_thread->name);
+}
+
+int main(void)
+{
+    puts("Start.");
+    parent_pid = thread_pid;
+
+    for (int i = 0; i < NUM_CHILDREN; ++i) {
+        snprintf(names[i], sizeof (names[i]), "child%2u", i + 1);
+        pids[i] = thread_create(stacks[i],
+                                sizeof (stacks[i]),
+                                PRIORITY_MAIN + 1,
+                                CREATE_WOUT_YIELD | CREATE_STACKTEST,
+                                child_fun,
+                                names[i]);
+    }
+
+    int last_iteration = 0;
+    for (int i = 0; i < NUM_ITERATIONS * NUM_CHILDREN; ++i) {
+        msg_t m;
+        msg_receive(&m);
+        int cur_iteration = (int) m.type;
+        char *child = (char *) m.content.ptr;
+
+        printf("Received message from %s, iteration %u / %u: %s\n",
+               child, cur_iteration, NUM_ITERATIONS,
+               cur_iteration >= last_iteration ? "okay" : "ERROR");
+
+        last_iteration = cur_iteration;
+        vtimer_usleep(25 * 1000);
+    }
+
+    puts("Done.");
+    return 0;
+}

tests/test_queue_fairness/tests/01-test

@@ -0,0 +1,44 @@
+#!/usr/bin/env expect
+
+set timeout 5
+
+set pid [spawn make term]
+puts "-*- Spawened $pid -*-\n"
+
+set result 0
+expect {
+    "Start." {}
+    timeout {
+        set result 1
+    }
+}
+
+while { $result == 0 } {
+    set result 1
+    expect {
+        "Received message" {
+            expect {
+                ": okay" { set result 0 }
+                ": ERROR" { set result 1 }
+                timeout { break }
+            }
+        }
+        "Done." {
+            set result 0
+            break
+        }
+        timeout { break }
+    }
+}
+
+if { $result == 0 } {
+    puts "\n-*- Test successful! -*-\n"
+} else {
+    puts "\n-*- TEST HAD ERRORS! -*-\n"
+}
+spawn kill -15 $pid
+sleep 1
+spawn kill -9 $pid
+wait
+close
+exit $result