tests/multi_net: Add test that requires queuing UDP packets.

This commit adds a new network multi-test which sends a burst of UDP
packets from the client, and the server doesn't recv them until they have
all been sent.

Signed-off-by: Damien George <damien@micropython.org>

tests/multi_net/udp_data_multi.py

@@ -0,0 +1,69 @@
+# Test UDP reception when there are multiple incoming UDP packets that need to be
+# queued internally in the TCP/IP stack.
+
+import socket
+
+NUM_NEW_SOCKETS = 4
+NUM_PACKET_BURSTS = 6
+NUM_PACKET_GROUPS = 5
+TOTAL_PACKET_BURSTS = NUM_NEW_SOCKETS * NUM_PACKET_BURSTS
+# The tast passes if more than 75% of packets are received in each group.
+PACKET_RECV_THRESH = 0.75 * TOTAL_PACKET_BURSTS
+PORT = 8000
+
+
+# Server
+def instance0():
+    recv_count = {i: 0 for i in range(NUM_PACKET_GROUPS)}
+    multitest.globals(IP=multitest.get_network_ip())
+    multitest.next()
+    for i in range(NUM_NEW_SOCKETS):
+        print("test socket", i)
+        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        s.bind(socket.getaddrinfo("0.0.0.0", PORT + i)[0][-1])
+        s.settimeout(0.250)
+        multitest.broadcast("server ready")
+        for burst in range(NUM_PACKET_BURSTS):
+            # Wait for all packets to be sent, without receiving any yet.
+            multitest.wait("data sent burst={}".format(burst))
+            # Try to receive all packets (they should be waiting in the queue).
+            for group in range(NUM_PACKET_GROUPS):
+                try:
+                    data, addr = s.recvfrom(1000)
+                except:
+                    continue
+                recv_burst, recv_group = data.split(b":")
+                recv_burst = int(recv_burst)
+                recv_group = int(recv_group)
+                if recv_burst == burst:
+                    recv_count[recv_group] += 1
+            # Inform the client that all data was received.
+            multitest.broadcast("data received burst={}".format(burst))
+        s.close()
+
+    # Check how many packets were received.
+    for group, count in recv_count.items():
+        if count >= PACKET_RECV_THRESH:
+            print("pass group={}".format(group))
+        else:
+            print("fail group={} received={}%".format(group, 100 * count // TOTAL_PACKET_BURSTS))
+
+
+# Client
+def instance1():
+    multitest.next()
+    for i in range(NUM_NEW_SOCKETS):
+        print("test socket", i)
+        ai = socket.getaddrinfo(IP, PORT + i)[0][-1]
+        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        multitest.wait("server ready")
+        for burst in range(NUM_PACKET_BURSTS):
+            # Send a bunch of packets all in a row.
+            for group in range(NUM_PACKET_GROUPS):
+                s.sendto(b"%d:%d" % (burst, group), ai)
+            # Inform the server that the data has been sent.
+            multitest.broadcast("data sent burst={}".format(burst))
+            # Wait for the server to finish receiving.
+            multitest.wait("data received burst={}".format(burst))
+        s.close()

tests/multi_net/udp_data_multi.py.exp

@@ -0,0 +1,15 @@
+--- instance0 ---
+test socket 0
+test socket 1
+test socket 2
+test socket 3
+pass group=0
+pass group=1
+pass group=2
+pass group=3
+pass group=4
+--- instance1 ---
+test socket 0
+test socket 1
+test socket 2
+test socket 3