tests/periph_dma: add automatic testing of DMA over UART

tests/periph_dma/main.c

@@ -21,7 +21,12 @@
 
 int main(void)
 {
-    puts("DMA dummy test app");
+    /*
+    This test is checking that DMA on UART is not broken when stdio UART is
+    configured with DMA.
+    Note that this message is also printed on 'normal' stdio UART (without DMA).
+    */
+    puts("DMA is working");
 
     return 0;
 }

tests/periph_dma/tests/01-run.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2019 Inria
+#
+# 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_exact('DMA is working')
+
+
+if __name__ == "__main__":
+    sys.exit(run(testfunc))