diff --git a/src/tests/test_overall.py b/src/tests/test_overall.py
--- a/src/tests/test_overall.py
+++ b/src/tests/test_overall.py
@@ -1,5 +1,4 @@
 import os
-import sys
 import shutil
 import hashlib
 import multiprocessing
@@ -8,7 +7,7 @@ from unittest import TestCase
 
 import config
 from hashtree import HashTree
-from client import Client, Connection as ClientConnection
+from client import Client, Connection as ClientConnection, DeniedConnection
 from server import Miniserver
 from . import RedirectedOutput
 
@@ -56,6 +55,7 @@ class TestMorevna(RedirectedOutput,TestC
 		os.remove(treeFile)
 
 	def test_push(self):
+		config.port+=1
 		ms=Miniserver(filename)
 		p=multiprocessing.Process(target=ms.serve)
 		p.start()
@@ -65,6 +65,7 @@ class TestMorevna(RedirectedOutput,TestC
 			c=Client(clientFile)
 			with ClientConnection("127.0.0.1",config.port) as con:
 				c.setConnection(con)
+				c.init("push")
 				blocksToTransfer=c.negotiate()
 				c.sendData(blocksToTransfer)
 
@@ -74,6 +75,7 @@ class TestMorevna(RedirectedOutput,TestC
 		p.join()
 
 	def test_pull(self):
+		config.port+=1
 		serverFile=os.path.join(dataDir,"test3.img")
 		ms=Miniserver(serverFile)
 		p=multiprocessing.Process(target=ms.serve)
@@ -82,6 +84,7 @@ class TestMorevna(RedirectedOutput,TestC
 		c=Client(filename)
 		with ClientConnection("127.0.0.1",config.port) as con:
 			c.setConnection(con)
+			c.init("pull")
 			blocksToTransfer=c.negotiate()
 			c.pullData(blocksToTransfer)
 
@@ -89,3 +92,24 @@ class TestMorevna(RedirectedOutput,TestC
 
 		p.terminate()
 		p.join()
+
+	def test_deny(self):
+		config.port+=1
+		ms=Miniserver(filename)
+		p=multiprocessing.Process(target=ms.serve)
+		p.start()
+
+		c1=Client(os.path.join(dataDir,"test2.img"))
+		with ClientConnection("127.0.0.1",config.port) as con1:
+			c1.setConnection(con1)
+			c1.init("push")
+
+			c2=Client(os.path.join(dataDir,"test3.img"))
+			with ClientConnection("127.0.0.1",config.port) as con2:
+				c2.setConnection(con2)
+				with self.assertRaises(DeniedConnection):
+					c2.init("push")
+			c1.sendData([]) # to unlock the server
+
+		p.terminate()
+		p.join()