feat(driver): wait for Squish server port to listen

Doing silly retries is just not reliable, this is.

Signed-off-by: Jakub Sokołowski <jakub@status.im>

test/e2e/driver/server.py

@@ -3,6 +3,7 @@ import typing
 
 import configs.testpath
 from scripts.utils import local_system
+from scripts.utils.wait_for_port import wait_for_port
 
 _PROCESS_NAME = '_squishserver'
 
@@ -40,6 +41,12 @@ class SquishServer:
             cls.pid = None
         cls.port = None
 
+    @classmethod
+    def wait(cls, timeout: int = 1, retries: int = 10):
+        LOG.info('Waiting for Squish server port %s:%d...', cls.host, cls.port)
+        wait_for_port(cls.host, cls.port, timeout, retries)
+        LOG.info('Squish server port available!')
+
     # https://doc-snapshots.qt.io/squish/cli-squishserver.html
     @classmethod
     def configuring(cls, action: str, options: typing.Union[int, str, list]):

test/e2e/scripts/utils/wait_for_port.py

@@ -0,0 +1,21 @@
+import time
+import socket
+import logging
+
+LOG = logging.getLogger(__name__)
+
+def wait_for_port(host: str, port: int, timeout: int = 1, retries: int = 0):
+    for i in range(retries+1):
+        try:
+            LOG.debug('Checking TCP port: %s:%d', host, port)
+            with socket.create_connection((host, port), timeout=timeout):
+                return
+        except OSError as err:
+            LOG.debug('Connection error: %s', err)
+            time.sleep(1)
+            continue
+
+    LOG.debug('Timed out waiting for TCP port: %s:%d', host, port)
+    raise TimeoutError(
+        'Unable to establish TCP connection with %s:%s.' % (host, port)
+    )