diff --git a/mail4one/pop_test.py b/mail4one/pop_test.py
index 661f794..af21e7a 100644
--- a/mail4one/pop_test.py
+++ b/mail4one/pop_test.py
@@ -2,6 +2,7 @@ import unittest
 import asyncio
 import logging
 from .pop3 import create_pop_server
+from .config import User
 
 
 class TestPop3(unittest.IsolatedAsyncioTestCase):
@@ -10,23 +11,30 @@ class TestPop3(unittest.IsolatedAsyncioTestCase):
         logging.basicConfig(level=logging.CRITICAL)
 
     async def asyncSetUp(self):
+        test_hash = "".join((l.strip() for l in """
+        AFTY5EVN7AX47ZL7UMH3BETYWFBTAV3XHR73CEFAJBPN2NIHPWD
+        ZHV2UQSMSPHSQQ2A2BFQBNC77VL7F2UKATQNJZGYLCSU6C43UQD
+        AQXWXSWNGAEPGIMG2F3QDKBXL3MRHY6K2BPID64ZR6LABLPVSF
+        """.splitlines()))
+        users = [
+            User(username="foobar", password_hash=test_hash, mbox="mails")
+        ]
         pop_server = await create_pop_server(host='127.0.0.1',
                                              port=7995,
                                              mails_path='w.tmp',
-                                             users=[])
+                                             users=users)
         self.task = asyncio.create_task(pop_server.serve_forever())
+        self.reader, self.writer = await asyncio.open_connection('127.0.0.1', 7995)
 
     async def test_QUIT(self):
-        reader, writer = await asyncio.open_connection('127.0.0.1', 7995)
         dialog = """
         S: +OK Server Ready
         C: QUIT
         S: +OK Bye
         """
-        await self.dialog_checker(reader, writer, dialog)
+        await self.dialog_checker(dialog)
 
     async def test_BAD(self):
-        reader, writer = await asyncio.open_connection('127.0.0.1', 7995)
         dialog = """
         S: +OK Server Ready
         C: HELO
@@ -37,12 +45,45 @@ class TestPop3(unittest.IsolatedAsyncioTestCase):
         S: -ERR Something went wrong
         C: HELO
         """
-        await self.dialog_checker(reader, writer, dialog)
+        await self.dialog_checker(dialog)
         # TODO fix
         # self.assertTrue(reader.at_eof(), "server should close the connection")
 
+    async def test_AUTH(self):
+        dialog = """
+        S: +OK Server Ready
+        C: USER foobar
+        S: +OK Welcome
+        C: PASS helloworld
+        S: +OK Login successful
+        C: QUIT
+        S: +OK Bye
+        """
+        await self.dialog_checker(dialog)
+
+    async def test_dupe_AUTH(self):
+        r1, w1 = await asyncio.open_connection('127.0.0.1', 7995)
+        r2, w2 = await asyncio.open_connection('127.0.0.1', 7995)
+        dialog = """
+        S: +OK Server Ready
+        C: USER foobar
+        S: +OK Welcome
+        C: PASS helloworld
+        """
+        await self.dialog_checker_impl(r1, w1, dialog)
+        await self.dialog_checker_impl(r2, w2, dialog)
+        d1 = """S: +OK Login successful"""
+        d2 = """S: -ERR Auth Failed: Already logged in"""
+        await self.dialog_checker_impl(r1, w1, d1)
+        await self.dialog_checker_impl(r2, w2, d2)
+        end_dialog = """
+        C: QUIT
+        S: +OK Bye
+        """
+        await self.dialog_checker_impl(r1, w1, end_dialog)
+        await self.dialog_checker_impl(r2, w2, end_dialog)
+
     async def test_CAPA(self):
-        reader, writer = await asyncio.open_connection('127.0.0.1', 7995)
         dialog = """
         S: +OK Server Ready
         C: CAPA
@@ -52,12 +93,17 @@ class TestPop3(unittest.IsolatedAsyncioTestCase):
         C: QUIT
         S: +OK Bye
         """
-        await self.dialog_checker(reader, writer, dialog)
+        await self.dialog_checker(dialog)
 
     async def asyncTearDown(self):
+        self.writer.close()
+        await self.writer.wait_closed()
         self.task.cancel("test done")
 
-    async def dialog_checker(self, reader: asyncio.StreamReader,
+    async def dialog_checker(self, dialog: str):
+        await self.dialog_checker_impl(self.reader, self.writer, dialog)
+
+    async def dialog_checker_impl(self, reader: asyncio.StreamReader,
                              writer: asyncio.StreamWriter, dialog: str):
         for line in dialog.splitlines():
             line = line.strip()