diff --git a/resolwe/flow/executors/socket_utils.py b/resolwe/flow/executors/socket_utils.py
index 71dde6582..4dc8f2f18 100644
--- a/resolwe/flow/executors/socket_utils.py
+++ b/resolwe/flow/executors/socket_utils.py
@@ -52,6 +52,16 @@ class PeerStatus(Enum):
     UNRESPONSIVE = "unresponsive"
 
 
+class ReceiveStatus(Enum):
+    """Status of the received method."""
+
+    OK = "OK"
+    INVALID_MESSAGE = "invalid"
+    CANCELLED = "cancelled"
+    SOCKET_CLOSED = "socket_closed"
+    TERMINATED = "terminated"
+
+
 PeerIdentity = bytes
 MessageDataType = TypeVar("MessageDataType")
 ResponseDataType = TypeVar("ResponseDataType")
@@ -563,7 +573,9 @@ def call_command(*args):
         else:
             return call_command
 
-    async def _receive_message(self) -> Optional[Tuple[PeerIdentity, Message]]:
+    async def _receive_message(
+        self,
+    ) -> Tuple[ReceiveStatus, Optional[Tuple[PeerIdentity, Message]]]:
         """Receive a single message.
 
         This method is blocking: it waits for the message to arrive. The
@@ -581,6 +593,7 @@ async def _receive_message(self) -> Optional[Tuple[PeerIdentity, Message]]:
             the key "type".
         """
         result = None
+        received_status = ReceiveStatus.INVALID_MESSAGE
         try:
             self.logger.debug("Communicator %s waiting for message.", self.name)
             receive_task = asyncio.ensure_future(self.receive_method(self.reader))
@@ -592,6 +605,7 @@ async def _receive_message(self) -> Optional[Tuple[PeerIdentity, Message]]:
                 try:
                     received = receive_task.result()
                 except asyncio.IncompleteReadError:
+                    received_status = ReceiveStatus.SOCKET_CLOSED
                     self.logger.info("Socket closed by peer, stopping communication.")
                     received = None
                 if received is not None:
@@ -601,17 +615,20 @@ async def _receive_message(self) -> Optional[Tuple[PeerIdentity, Message]]:
                     received[1]["client_id"] = received[2]
                     assert Message.is_valid(received[1])
                     result = received[0], Message.from_dict(received[1])
+                    received_status = ReceiveStatus.OK
             else:
+                received_status = ReceiveStatus.TERMINATED
                 self.logger.debug(
                     "Communicator %s _receive_message: terminating flag is set, returning None",
                     self.name,
                 )
-        # Do not log cancelled errors.
         except asyncio.CancelledError:
+            received_status = ReceiveStatus.CANCELLED
             self.logger.debug(
                 "Communicator %s: CancelledError in _receive_message.", self.name
             )
         except:
+            received_status = ReceiveStatus.INVALID_MESSAGE
             self.logger.exception(
                 "Communicator %s: exception in _receive_message.", self.name
             )
@@ -619,7 +636,7 @@ async def _receive_message(self) -> Optional[Tuple[PeerIdentity, Message]]:
             # Always stop both tasks.
             receive_task.cancel()
             terminating_task.cancel()
-        return result
+        return received_status, result
 
     async def _send_message(
         self,
@@ -714,13 +731,17 @@ async def start_listening(self):
         """
         try:
             while True:
-                received = await self._receive_message()
+                status, received = await self._receive_message()
 
                 if received is None:
-                    self.logger.info(
-                        f"Communicator {self.name}: received empty message, closing communicator."
-                    )
-                    break
+                    if status in [
+                        ReceiveStatus.SOCKET_CLOSED,
+                        ReceiveStatus.TERMINATED,
+                        ReceiveStatus.CANCELLED,
+                    ]:
+                        break
+                    elif ReceiveStatus.INVALID_MESSAGE:
+                        continue
 
                 identity, message = received
 
diff --git a/resolwe/flow/executors/zeromq_utils.py b/resolwe/flow/executors/zeromq_utils.py
index 2fa2d1230..d44d87b99 100644
--- a/resolwe/flow/executors/zeromq_utils.py
+++ b/resolwe/flow/executors/zeromq_utils.py
@@ -2,7 +2,6 @@
 
 import json
 import os
-from contextlib import suppress
 from logging import Logger
 from threading import Lock
 from typing import Any, Optional, Tuple
@@ -102,14 +101,3 @@ def instance(cls, context=None):
                     cls._instance = cls(context=context)
                     cls._instance_pid = os.getpid()
         return cls._instance
-
-    def start(self):
-        """Ignore possible exception when testing."""
-        # The is_testing is not available in the executor so it is imported here.
-        from resolwe.test.utils import is_testing
-
-        if is_testing():
-            with suppress(zmq.error.ZMQError):
-                super().start()
-        else:
-            super().start()
diff --git a/resolwe/flow/tests/test_filtering.py b/resolwe/flow/tests/test_filtering.py
index 74cb232a5..628a8abca 100644
--- a/resolwe/flow/tests/test_filtering.py
+++ b/resolwe/flow/tests/test_filtering.py
@@ -70,9 +70,6 @@ def _check_filter(
         request = factory.get("/", query_args, format="json")
         force_authenticate(request, user or self.admin)
         response = self.viewset(request)
-        print("Got response")
-        print(response)
-        print(response.data)
 
         if status.is_success(response.status_code):
             self.assertEqual(len(response.data), len(expected))
diff --git a/resolwe/test_helpers/test_runner.py b/resolwe/test_helpers/test_runner.py
index 097cf687d..24c7983cd 100644
--- a/resolwe/test_helpers/test_runner.py
+++ b/resolwe/test_helpers/test_runner.py
@@ -329,6 +329,8 @@ async def _run_on_infrastructure(meth, *args, **kwargs):
                         logger.exception("Exception while running test")
                     finally:
                         zmq_info.authenticator.stop()
+                        # Make sure authenticator task is stopped.
+                        await asyncio.sleep(0.1)
                         logger.debug("test_runner: Terminating listener")