Extend workflow time and fix debian serial port bug (ros-drivers#145)

Fix the Github workflow CI build:
- Extend the timeout from 10 minutes to 30 minutes because the worker was observed idling 9 minutes of the 10 minute threshold in https://github.com/ros-drivers/nmea_navsat_driver/runs/5672759022?check_suite_focus=true.
- Change how the virtual serial port script waits for the ports, because the ROS buildfarm debian builder seems to have an inconsistent behavior concerning the time it takes to open virtual serial ports, causing the build to crash sometimes.

.github/workflows/ci.yaml

@@ -3,7 +3,7 @@ on: [push, pull_request]
 jobs:
   test:
     runs-on: [ubuntu-latest]
-    timeout-minutes: 10
+    timeout-minutes: 30
     strategy:
       matrix:
         ros_distro: [noetic]

test/test_driver.py

@@ -112,13 +112,23 @@ def check_msg(self, msg, log, topic):
     @staticmethod
     def create_vsps():
         """Create virtual serial ports (vsp) for serial driver testing."""
+        ports = []
         f = io.StringIO()
         with redirect_stdout(f):
             th_vsp = threading.Thread(target=virtualserialports.run, args=(2, False, False))
             th_vsp.daemon = True
             th_vsp.start()
 
-        return f.getvalue().split('\n')[:-1]
+            rospy.sleep(2.)
+
+        while len(ports) < 2:
+            ports = f.getvalue().split('\n')[:-1]
+
+            if len(ports) < 2:
+                rospy.logwarn('Virtual serial ports not ready yet, waiting...')
+                rospy.sleep(2.)
+
+        return ports
 
     def playback_log(self, launchfile, log):
         """Playback a logfile."""
@@ -185,12 +195,9 @@ def test(self):
         p_roscore = subprocess.Popen(['roscore'], env=env_variables)
         rospy.init_node('nmea_navsat_driver_tester')
 
-        # init serial handler and wait until vsps are ready
+        # init serial handler
         ports = self.create_vsps()
         self.serial_writer = serial.Serial(ports[0], 115200)
-        while len(ports) < 2:
-            rospy.logwarn('Virtual serial ports not ready yet, waiting...')
-            rospy.sleep(.5)
 
         # process all launch files
         for launchfile in self.cfg_launches: