test/case: Add meta/wait to wait for nodes to boot up

When running in the cloud, without KVM emulation, together with many
other tenants, it can take a very long time to boot the instances.

Therefore, add a meta test that will wait for all devices in the
physical topology to come up before exiting. This means that the
actual test cases that follow can assume that devices will answer
NETCONF requests.

test/case/all.yaml

@@ -1,4 +1,6 @@
 ---
+- case: meta/wait.py
+
 - name:  ietf-system
   suite: ietf_system/all.yaml
 

test/case/meta/wait.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+
+import socket
+import time
+
+import infamy, infamy.neigh
+
+def ll6ping(node):
+    neigh = None
+
+    for (_, cport), (_, nport) in env.ptop.get_paths(ctrl, node):
+        neigh = infamy.neigh.ll6ping(cport, flags=["-w1", "-c1", "-L", "-n"])
+        if neigh:
+            print(f"Found {neigh} on {cport} (connected to {node}:{nport})")
+            break
+
+    return neigh
+
+def netconf_syn(neigh):
+    try:
+        ai = socket.getaddrinfo(neigh, 830, 0, 0, socket.SOL_TCP)
+        sock = socket.socket(ai[0][0], ai[0][1], 0)
+        sock.connect(ai[0][4])
+        sock.close()
+        print(f"{neigh} answers to TCP connections on port 830 (NETCONF)")
+        return True
+    except:
+        return False
+
+with infamy.Test() as test:
+    with test.step("Initialize"):
+        env = infamy.Env()
+
+        ctrl = env.ptop.get_ctrl()
+        infixen = env.ptop.get_infixen()
+
+    with test.step(f"Reach {infixen}"):
+        timeout = time.time() + 300
+
+        print(f"Waiting a maximum of 5min for {infixen} to come up")
+
+        while infixen and time.time() < timeout:
+            time.sleep(1)
+            retry = []
+            for node in infixen:
+                neigh = ll6ping(node)
+                if neigh and netconf_syn(neigh):
+                    continue
+
+                retry.append(node)
+
+            infixen = retry
+
+        if infixen:
+            print(f"Unable to reach {infixen}")
+            test.fail()
+
+    test.succeed()