tests/periph_hwrng: add automated python test

Add the automated test for 'periph_hwrng'. It only checks that numbers
are returned, not their value.

tests/periph_hwrng/tests/01-run.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2019 Freie Universität Berlin
+#
+# 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.
+
+"""periph_hwrng test
+
+Automatic checking of the periph_hwrng firmware.
+It checks the output is valid but not the number themselves.
+"""
+
+import sys
+from testrunner import run
+
+
+def testfunc(child):
+    """Test generating several numbers
+
+    It prints hardware generated random bytes buffer from increasing size.
+    The generated random numbers are not checked.
+    """
+    child.expect_exact('HWRNG peripheral driver test')
+    child.expect(r'This test will print from 1 to (\d+)'
+                 ' random bytes about every second')
+    iterations = int(child.match.group(1))
+
+    for num in range(1, iterations + 1):
+        child.expect_exact('generating %u random byte(s)' % num)
+        generated = 'Got:' + num * (r' 0x[0-9a-fA-F]{2}')
+        child.expect(generated)
+
+
+if __name__ == "__main__":
+    sys.exit(run(testfunc))