Improve array creation

This fixes an issue where numpy guessed type mismatched with the given dtype. For example, int64 VS uint64.

beat/backend/python/test/test_databases_provider.py

@@ -29,9 +29,8 @@
 # Tests for experiment execution
 
 import os
-
+import socket
 import logging
-logger = logging.getLogger(__name__)
 
 import unittest
 import json
@@ -39,9 +38,12 @@ import multiprocessing
 import tempfile
 import shutil
 import zmq
+
 from time import time
 from time import sleep
 
+from contextlib import closing
+
 from ..scripts import databases_provider
 from ..database import Database
 from ..data import RemoteDataSource
@@ -50,6 +52,9 @@ from ..data import RemoteException
 from . import prefix
 
 
+logger = logging.getLogger(__name__)
+
+
 #----------------------------------------------------------
 
 
@@ -197,8 +202,13 @@ class TestDatabasesProvider(unittest.TestCase):
         view = database.view(input_cfg['protocol'], input_cfg['set'])
         view.index(os.path.join(self.cache_root, input_cfg['path']))
 
+        with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as s:
+            s.bind(('', 0))
+            port = s.getsockname()[1]
+
+        address = '127.0.0.1:%i' % port
         args = [
-            '127.0.0.1:50000',
+            address,
             self.working_dir,
             self.cache_root,
         ]
@@ -210,7 +220,7 @@ class TestDatabasesProvider(unittest.TestCase):
 
         self.client_context = zmq.Context()
         self.client_socket = self.client_context.socket(zmq.PAIR)
-        self.client_socket.connect('tcp://127.0.0.1:50000')
+        self.client_socket.connect('tcp://%s' % address)
 
         dataformat_name = database.set(input_cfg['protocol'], input_cfg['set'])['outputs'][input_cfg['output']]