tests/periph_uart_nonblocking: add simple test application

The application is mainly to compile-test non-blocking UART
functionality, but some functional testing is also possible.

With non-blocking UART the total runtime of the program is 2100735 µs
on same54-xpro.
With blocking UART the total runtime is 2152407 µs.

tests/periph_uart_nonblocking/Makefile

@@ -0,0 +1,6 @@
+include ../Makefile.tests_common
+
+FEATURES_REQUIRED += periph_uart_nonblocking
+USEMODULE += xtimer
+
+include $(RIOTBASE)/Makefile.include

tests/periph_uart_nonblocking/main.c

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2019 Benjamin Valentin <benpicco@googlemail.com>
+ *
+ * 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       Simple test application for non-blocking UART functionality
+ *
+ * @author      Benjamin Valentin <benpicco@googlemail.com>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+#include <xtimer.h>
+
+#define LINE_DELAY_MS   100
+
+static inline uint32_t puts_delay(const char* str)
+{
+    puts(str);
+    xtimer_usleep(LINE_DELAY_MS * 1000);
+    return LINE_DELAY_MS * 1000;
+}
+
+int main(void)
+{
+    uint32_t total_us = 0;
+    xtimer_ticks32_t counter = xtimer_now();
+
+    /* Richard Stallman and the Free Software Foundation
+       claim no copyright on this song. */
+    total_us += puts_delay("");
+    total_us += puts_delay("Join us now and share the software;");
+    total_us += puts_delay("You'll be free, hackers, you'll be free.");
+    total_us += puts_delay("Join us now and share the software;");
+    total_us += puts_delay("You'll be free, hackers, you'll be free.");
+    total_us += puts_delay("");
+    total_us += puts_delay("Hoarders can get piles of money,");
+    total_us += puts_delay("That is true, hackers, that is true.");
+    total_us += puts_delay("But they cannot help their neighbors;");
+    total_us += puts_delay("That's not good, hackers, that's not good.");
+    total_us += puts_delay("");
+    total_us += puts_delay("When we have enough free software");
+    total_us += puts_delay("At our call, hackers, at our call,");
+    total_us += puts_delay("We'll kick out those dirty licenses");
+    total_us += puts_delay("Ever more, hackers, ever more.");
+    total_us += puts_delay("");
+    total_us += puts_delay("Join us now and share the software;");
+    total_us += puts_delay("You'll be free, hackers, you'll be free.");
+    total_us += puts_delay("Join us now and share the software;");
+    total_us += puts_delay("You'll be free, hackers, you'll be free.");
+    total_us += puts_delay("");
+
+    counter.ticks32 = xtimer_now().ticks32 - counter.ticks32;
+
+    printf("== printed in %" PRIu32 "/%" PRIu32 " µs ==\n", xtimer_usec_from_ticks(counter), total_us);
+
+    puts("[SUCCESS]");
+
+    return 0;
+}

tests/periph_uart_nonblocking/tests/01-run.py

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+#!/usr/bin/env python3
+
+# Copyright (C) 2019 Benjamin Valentin
+#
+# 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.
+
+import sys
+from testrunner import run
+
+
+def testfunc(child):
+    child.expect(r'== printed in (\d+)/(\d+) µs ==')
+    time_actual = int(child.match.group(1))
+    time_expect = int(child.match.group(2))
+
+    assert time_actual / time_expect < 1.0015
+
+    child.expect_exact("[SUCCESS]")
+
+
+if __name__ == "__main__":
+    sys.exit(run(testfunc))