[test][worker] Get random port rather than using a fixed number

This will allow to run several tests in parallel.

beat/core/test/test_worker.py

@@ -46,15 +46,16 @@ from time import sleep
 from ..scripts import worker
 from ..worker import WorkerController
 from ..database import Database
+from ..utils import find_free_port
 
 from . import prefix, tmp_prefix
 
-
 #----------------------------------------------------------
 
 
 WORKER1 = b'worker1'
 WORKER2 = b'worker2'
+PORT = find_free_port()
 
 
 #----------------------------------------------------------
@@ -151,7 +152,7 @@ class ControllerProcess(multiprocessing.Process):
 
         self.controller = WorkerController(
             '127.0.0.1',
-            port=50999,
+            port=PORT,
             callbacks=dict(
                 onWorkerReady = onWorkerReady,
                 onWorkerGone = onWorkerGone,
@@ -347,10 +348,10 @@ class TestConnection(TestWorkerBase):
 
 
     def test_scheduler_last(self):
-        self.start_worker(WORKER1, address='tcp://127.0.0.1:50999')
+        self.start_worker(WORKER1, address='tcp://127.0.0.1:%i' % PORT)
         sleep(1)
 
-        self.start_controller(port=50999)
+        self.start_controller(port=PORT)
 
         self.wait_for_worker_connection(WORKER1)
 
@@ -362,7 +363,7 @@ class TestConnection(TestWorkerBase):
         message = controller.queue.get()
         self.assertEqual(message, 'STARTED')
 
-        self.start_worker(WORKER1, 'tcp://127.0.0.1:50999')
+        self.start_worker(WORKER1, 'tcp://127.0.0.1:%i' % PORT)
 
         message = controller.queue.get()
         self.assertEqual(message, 'READY ' + WORKER1.decode())