diff --git a/aiossdb/__init__.py b/aiossdb/__init__.py
index cb6ab5d..8831b34 100644
--- a/aiossdb/__init__.py
+++ b/aiossdb/__init__.py
@@ -1,7 +1,8 @@
 from .connection import create_connection, SSDBConnection
-from .errors import SSDBError, ReplyError, ConnectionClosedError, ProtocolError
+from .errors import SSDBError, ReplyError, ConnectionClosedError, ProtocolError, PoolClosedError
 from .parser import SSDBParser
 from .pool import create_pool, SSDBConnectionPool
+from .client import Client
 
 __version__ = '0.0.1'
 __author__ = "Kevin Du"
diff --git a/aiossdb/client.py b/aiossdb/client.py
index 54a5fbd..709994a 100644
--- a/aiossdb/client.py
+++ b/aiossdb/client.py
@@ -42,3 +42,4 @@ def close(self):
         if self._pool:
             self._pool.close()
             yield from self._pool.wait_closed()
+            self._pool = None
diff --git a/aiossdb/log.py b/aiossdb/log.py
index 7568ac2..39ecbb2 100644
--- a/aiossdb/log.py
+++ b/aiossdb/log.py
@@ -1,14 +1,14 @@
-import os
-import sys
+# import os
+# import sys
 import logging
 
 
 logger = logging.getLogger('aiossdb')
 
-if os.environ.get("AIOSSDB_DEBUG"):
-    logger.setLevel(logging.DEBUG)
-    handler = logging.StreamHandler(stream=sys.stderr)
-    handler.setFormatter(logging.Formatter(
-        "%(asctime)s %(name)s %(levelname)s %(message)s"))
-    logger.addHandler(handler)
-    os.environ["AIOSSDB_DEBUG"] = ""
+# if os.environ.get("AIOSSDB_DEBUG"):
+#     logger.setLevel(logging.DEBUG)
+#     handler = logging.StreamHandler(stream=sys.stderr)
+#     handler.setFormatter(logging.Formatter(
+#         "%(asctime)s %(name)s %(levelname)s %(message)s"))
+#     logger.addHandler(handler)
+#     os.environ["AIOSSDB_DEBUG"] = ""
diff --git a/aiossdb/pool.py b/aiossdb/pool.py
index 3e25968..54a5f8c 100644
--- a/aiossdb/pool.py
+++ b/aiossdb/pool.py
@@ -220,6 +220,7 @@ def _do_close(self):
             yield from asyncio.gather(*waiters, loop=self._loop)
             self._closed = True
 
+    @asyncio.coroutine
     def wait_closed(self):
         """等待直到连接池关闭，这里要等待的是所有连接池连接的关闭期物Future的完成"""
         yield from asyncio.shield(self._waiter, loop=self._loop)
diff --git a/tests/client_test.py b/tests/client_test.py
index e69de29..40258f6 100644
--- a/tests/client_test.py
+++ b/tests/client_test.py
@@ -0,0 +1,24 @@
+import pytest
+from aiossdb import Client
+
+
+@pytest.mark.asyncio
+async def test_create_client(event_loop):
+    c = Client(loop=event_loop)
+    assert c._pool is None
+    pool = await c.get_pool()
+    assert pool is c._pool
+    assert c._pool.maxsize == c.max_connection
+    await c.close()
+    assert c._pool is None
+
+
+@pytest.mark.asyncio
+async def test_execute_command(event_loop):
+    c = Client(loop=event_loop)
+    await c.set('a', 1)
+    res = await c.get('a')
+    assert res[0] == '1'
+    assert c._pool is not None
+    await c.close()
+    assert c._pool is None
diff --git a/tests/connection_pool_test.py b/tests/connection_pool_test.py
index 8bd3786..b00bbf0 100644
--- a/tests/connection_pool_test.py
+++ b/tests/connection_pool_test.py
@@ -1,5 +1,5 @@
 import pytest
-from aiossdb import SSDBConnectionPool, SSDBConnection, ReplyError
+from aiossdb import SSDBConnectionPool, SSDBConnection, ReplyError, PoolClosedError
 
 
 def _assert_defaults(pool):
@@ -9,6 +9,7 @@ def _assert_defaults(pool):
     assert pool.size == 1
     assert pool.freesize == 1
     assert pool._waiter is None
+    assert str(pool) == '<SSDBConnectionPool [size:[1:10], free:1]>'
 
 
 @pytest.mark.asyncio
@@ -34,6 +35,7 @@ async def test_get_connection(pool):
 
 @pytest.mark.asyncio
 async def test_execute_commands(pool):
+    await pool.auth('')
     await pool.execute('set', 'a', 1)
 
     res = await pool.execute('get', 'a')
@@ -75,4 +77,42 @@ async def test_more_connections(pool):
     assert pool.freesize == 2
     assert pool.size == 2
 
+    conn1.close()
+    await conn1.wait_closed()
 
+    pool._drop_closed()
+
+    assert pool.freesize == 1
+    assert pool.size == 1
+
+    pool.close()
+    await pool.wait_closed()
+
+    assert pool.closed
+
+    with pytest.raises(PoolClosedError):
+        await pool.release(conn2)
+
+
+@pytest.mark.asyncio
+async def test_close_pool(pool):
+
+    conn, addr = await pool.get_connection()
+    await pool.release(conn)
+    assert pool.freesize == 1
+    assert pool.size == 1
+
+    conn.close()
+    await conn.wait_closed()
+
+    conn, addr = await pool.get_connection()
+    assert pool.freesize == 0
+    assert pool.size == 1
+
+    pool.close()
+    await pool.wait_closed()
+
+    assert pool.closed
+
+    with pytest.raises(PoolClosedError):
+        await pool.new_connection()
\ No newline at end of file
diff --git a/tests/connection_test.py b/tests/connection_test.py
index 5836455..30d7d49 100644
--- a/tests/connection_test.py
+++ b/tests/connection_test.py
@@ -194,4 +194,4 @@ async def test_execute_commands(create_connection, event_loop, local_server):
 
     conn = await create_connection(address, loop=event_loop, password='')
 
-    assert not conn.closed
\ No newline at end of file
+    assert not conn.closed