server: tests: ci ensure the server is stopped before scenario, and do not quit while the server is listening

examples/server/tests/features/environment.py

@@ -1,8 +1,38 @@
+import multiprocessing
+import os
+import socket
+import subprocess
 import time
+from contextlib import closing
+from signal import SIGKILL
+
+
+def before_scenario(context, scenario):
+    if is_server_listening("localhost", 8080):
+        assert False, "Server already started"
 
 
 def after_scenario(context, scenario):
-    print("stopping server...")
+    print(f"stopping server pid={context.server_process.pid} ...")
     context.server_process.kill()
-    # Wait few for socket to be free up
-    time.sleep(0.05)
+    # Wait few for socket to free up
+    time.sleep(0.1)
+
+    attempts = 0
+    while is_server_listening(context.server_fqdn, context.server_port):
+        print(f"stopping server pid={context.server_process.pid} ...")
+        os.kill(context.server_process.pid, SIGKILL)
+        time.sleep(0.5)
+        attempts += 1
+        if attempts > 1:
+            print(f"Server dandling exits, killing all {context.server_path} ...")
+            process = subprocess.run(['killall', '-9', context.server_path],
+                                     stderr=subprocess.PIPE,
+                                     universal_newlines=True)
+            print(process)
+
+
+def is_server_listening(server_fqdn, server_port):
+    with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as sock:
+        result = sock.connect_ex((server_fqdn, server_port))
+        return result == 0