diff --git a/.github/workflows/selfdrive_tests.yaml b/.github/workflows/selfdrive_tests.yaml
index 9d92392b3a..ea20612c16 100644
--- a/.github/workflows/selfdrive_tests.yaml
+++ b/.github/workflows/selfdrive_tests.yaml
@@ -209,6 +209,7 @@ jobs:
                         $UNIT_TEST system/loggerd && \
                         $UNIT_TEST selfdrive/car && \
                         $UNIT_TEST selfdrive/locationd && \
+                        $UNIT_TEST system/tests && \
                         $UNIT_TEST system/ubloxd && \
                         selfdrive/locationd/test/_test_locationd_lib.py && \
                         ./system/ubloxd/tests/test_glonass_runner && \
diff --git a/system/logmessaged.py b/system/logmessaged.py
index 280a23cf1d..8f24471941 100755
--- a/system/logmessaged.py
+++ b/system/logmessaged.py
@@ -12,7 +12,7 @@ def main() -> NoReturn:
   log_handler.setFormatter(SwagLogFileFormatter(None))
   log_level = 20  # logging.INFO
 
-  ctx = zmq.Context().instance()
+  ctx = zmq.Context.instance()
   sock = ctx.socket(zmq.PULL)
   sock.bind("ipc:///tmp/logmessage")
 
@@ -20,23 +20,32 @@ def main() -> NoReturn:
   log_message_sock = messaging.pub_sock('logMessage')
   error_log_message_sock = messaging.pub_sock('errorLogMessage')
 
-  while True:
-    dat = b''.join(sock.recv_multipart())
-    level = dat[0]
-    record = dat[1:].decode("utf-8")
-    if level >= log_level:
-      log_handler.emit(record)
+  try:
+    while True:
+      dat = b''.join(sock.recv_multipart())
+      level = dat[0]
+      record = dat[1:].decode("utf-8")
+      if level >= log_level:
+        log_handler.emit(record)
 
-    # then we publish them
-    msg = messaging.new_message()
-    msg.logMessage = record
-    log_message_sock.send(msg.to_bytes())
+      if len(record) > 2*1024*1024:
+        print("WARNING: log too big to publish", len(record))
+        print(print(record[:100]))
+        continue
 
-    if level >= 40:  # logging.ERROR
+      # then we publish them
       msg = messaging.new_message()
-      msg.errorLogMessage = record
-      error_log_message_sock.send(msg.to_bytes())
-
+      msg.logMessage = record
+      log_message_sock.send(msg.to_bytes())
+
+      if level >= 40:  # logging.ERROR
+        msg = messaging.new_message()
+        msg.errorLogMessage = record
+        error_log_message_sock.send(msg.to_bytes())
+  finally:
+    sock.close()
+    ctx.term()
+    log_handler.close()
 
 if __name__ == "__main__":
   main()
diff --git a/system/tests/__init__.py b/system/tests/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/system/tests/test_logmessaged.py b/system/tests/test_logmessaged.py
new file mode 100755
index 0000000000..08335517ae
--- /dev/null
+++ b/system/tests/test_logmessaged.py
@@ -0,0 +1,60 @@
+#!/usr/bin/env python3
+import glob
+import os
+import shutil
+import time
+import unittest
+
+import cereal.messaging as messaging
+from selfdrive.manager.process_config import managed_processes
+from system.swaglog import cloudlog, SWAGLOG_DIR
+
+
+class TestLogmessaged(unittest.TestCase):
+
+  def setUp(self):
+    if os.path.exists(SWAGLOG_DIR):
+      shutil.rmtree(SWAGLOG_DIR)
+
+    managed_processes['logmessaged'].start()
+    self.sock = messaging.sub_sock("logMessage", timeout=1000, conflate=False)
+    self.error_sock = messaging.sub_sock("logMessage", timeout=1000, conflate=False)
+
+    # ensure sockets are connected
+    time.sleep(0.2)
+    messaging.drain_sock(self.sock)
+    messaging.drain_sock(self.error_sock)
+
+  def tearDown(self):
+    del self.sock
+    del self.error_sock
+    managed_processes['logmessaged'].stop(block=True)
+
+  def _get_log_files(self):
+    return list(glob.glob(os.path.join(SWAGLOG_DIR, "swaglog.*")))
+
+  def test_simple_log(self):
+    msgs = [f"abc {i}" for i in range(10)]
+    for m in msgs:
+      cloudlog.error(m)
+    time.sleep(3)
+    m = messaging.drain_sock(self.sock)
+    assert len(m) == len(msgs)
+    assert len(self._get_log_files()) >= 1
+
+  def test_big_log(self):
+    n = 10
+    msg = "a"*3*1024*1024
+    for _ in range(n):
+      cloudlog.info(msg)
+    time.sleep(3)
+
+    msgs = messaging.drain_sock(self.sock)
+    assert len(msgs) == 0
+
+    logsize = sum([os.path.getsize(f) for f in self._get_log_files()])
+    assert (n*len(msg)) < logsize < (n*(len(msg)+1024))
+
+
+if __name__ == "__main__":
+  unittest.main()