riotctrl_shell.gnrc: fix some more ping6 parsing errors

Found during integration of release tests:

- if the payload is too small, RTTs are not shown
- duplicates are now shown properly, if duplicates exist, the stats are
  now parsed instead of ignored

dist/pythonlibs/riotctrl_shell/gnrc.py

@@ -22,9 +22,18 @@ class GNRCICMPv6EchoParser(ShellInteractionParser):
     def _add_reply(res, reply):
         reply["seq"] = int(reply["seq"])
         reply["ttl"] = int(reply["ttl"])
-        reply["rtt"] = float(reply["rtt"])
+        if reply.get("rtt") is not None:
+            reply["rtt"] = float(reply["rtt"])
+        else:
+            reply.pop("rtt", None)
+        if reply.get("dup"):
+            reply["dup"] = True
+        else:
+            reply.pop("dup", None)
         if reply.get("rssi") is not None:
             reply["rssi"] = int(reply["rssi"])
+        else:
+            reply.pop("rssi", None)
         if "replies" in res:
             res["replies"].append(reply)
         else:
@@ -35,6 +44,10 @@ class GNRCICMPv6EchoParser(ShellInteractionParser):
         stats["packet_loss"] = int(stats["packet_loss"])
         stats["rx"] = int(stats["rx"])
         stats["tx"] = int(stats["tx"])
+        if stats.get("dup") is not None:
+            stats["dup"] = int(stats["dup"])
+        else:
+            stats.pop("dup")
         res["stats"] = stats
 
     @staticmethod
@@ -94,11 +107,13 @@ class GNRCICMPv6EchoParser(ShellInteractionParser):
         """
         res = {}
         c_reply = re.compile(r"\d+ bytes from (?P<source>[0-9a-f:]+(%\S+)?): "
-                             r"icmp_seq=(?P<seq>\d+) ttl=(?P<ttl>\d+) "
-                             r"(rssi=(?P<rssi>-?\d+) dBm )?"
-                             r"time=(?P<rtt>\d+.\d+) ms")
+                             r"icmp_seq=(?P<seq>\d+) ttl=(?P<ttl>\d+)"
+                             r"( rssi=(?P<rssi>-?\d+) dBm)?"
+                             r"( time=(?P<rtt>\d+.\d+) ms)?"
+                             r"(?P<dup> \(DUP\))?")
         c_stats = re.compile(r"(?P<tx>\d+) packets transmitted, "
                              r"(?P<rx>\d+) packets received, "
+                             r"((?P<dup>\d+) duplicates, )?"
                              r"(?P<packet_loss>\d+)% packet loss")
         c_rtts = re.compile(r"round-trip min/avg/max = (?P<min>\d+.\d+)/"
                             r"(?P<avg>\d+.\d+)/(?P<max>\d+.\d+) ms")
@@ -116,9 +131,7 @@ class GNRCICMPv6EchoParser(ShellInteractionParser):
                 m = c_rtts.match(line)
                 if m is not None:
                     self._set_rtts(res, m.groupdict())
-                    return res
-        # Unable to parse RTTs, so something went wrong.
-        return None
+        return res
 
 
 class GNRCPktbufStatsResults(dict):

dist/pythonlibs/riotctrl_shell/tests/test_gnrc.py

@@ -19,7 +19,7 @@ def test_ping6():
     assert " -i 100 " in res
 
 
-def test_ping6_parser_success():
+def test_ping6_parser_success1():
     parser = riotctrl_shell.gnrc.GNRCICMPv6EchoParser()
     ping_res = parser.parse("""
 12 bytes from ::1: icmp_seq=0 ttl=64 time=0.435 ms
@@ -29,27 +29,46 @@ def test_ping6_parser_success():
 --- ::1 PING statistics ---
 3 packets transmitted, 3 packets received, 0% packet loss
 round-trip min/avg/max = 0.432/0.433/0.435 ms""")
-    assert ping_res is not None
+    assert ping_res
     assert "rtts" in ping_res
     assert "avg" in ping_res["rtts"]
 
 
+def test_ping6_parser_success2():
+    parser = riotctrl_shell.gnrc.GNRCICMPv6EchoParser()
+    ping_res = parser.parse("""
+12 bytes from ::1: icmp_seq=0 ttl=64
+12 bytes from ::1: icmp_seq=1 ttl=64
+12 bytes from ::1: icmp_seq=1 ttl=64 (DUP)
+
+--- ::1 PING statistics ---
+2 packets transmitted, 3 packets received, 1 duplicates, 0% packet loss
+round-trip min/avg/max = 0.432/0.433/0.435 ms""")
+    assert ping_res
+    assert "rtts" in ping_res
+    assert "avg" in ping_res["rtts"]
+    assert len(ping_res["replies"]) == 3
+    assert ping_res["replies"][2]["dup"]
+
+
 def test_ping6_parser_empty():
     parser = riotctrl_shell.gnrc.GNRCICMPv6EchoParser()
     ping_res = parser.parse("")
-    assert ping_res is None
+    assert not ping_res
 
 
 def test_ping6_parser_missing_rtts():
     parser = riotctrl_shell.gnrc.GNRCICMPv6EchoParser()
     ping_res = parser.parse("""
-12 bytes from ::1: icmp_seq=0 ttl=64 time=0.553 ms
-12 bytes from ::1: icmp_seq=1 ttl=64 time=0.496 ms
-12 bytes from ::1: icmp_seq=2 ttl=64 time=0.496 ms
+12 bytes from ::1: icmp_seq=0 ttl=64
+12 bytes from ::1: icmp_seq=1 ttl=64
+12 bytes from ::1: icmp_seq=2 ttl=64
 
 --- ::1 PING statistics ---
 3 packets transmitted, 3 packets received, 0% packet loss""")
-    assert ping_res is None
+    assert ping_res
+    assert "rtts" not in ping_res
+    assert len(ping_res["replies"]) == 3
 
 
 def test_pktbuf():