diff --git a/README.rst b/README.rst
index 3e0671c..6049c3e 100755
--- a/README.rst
+++ b/README.rst
@@ -45,14 +45,14 @@ Shortcut
 --------
 
 Manual usage is too board. So I make shortcut to use easily.
-You just replace ``aiohttp.ClientSession`` to ``aiohttp_doh.ClientSession``.
+You just replace ``aiohttp.ClientSession`` to ``aiohttp_doh.DNSOverHTTPSClientSession``.
 
 .. code-block:: python3
 
-   from aiohttp_doh import ClientSession
+   from aiohttp_doh import DNSOverHTTPSClientSession
 
    async def main():
-       async with ClientSession() as session:
+       async with DNSOverHTTPSClientSession() as session:
            async with session.get('http://example.com') as resp:
                data = await resp.text()
 
@@ -68,7 +68,7 @@ endpoints
   List of str. DNS over HTTPS endpoints.
   Shortcut use `'https://dns.google.com/resolve'`
   and `'https://cloudflare-dns.com/dns-query'` both in default.
-  You can also use others instead.
+  You can also use others instead, make sure DNS endpoints support JSON response format (application/dns-json)
 
 json_loads
   Function for loads json. default is Python builtin json module's one.
diff --git a/aiohttp_doh.py b/aiohttp_doh.py
index 165646d..bbf69a3 100644
--- a/aiohttp_doh.py
+++ b/aiohttp_doh.py
@@ -9,7 +9,7 @@
 from aiohttp.connector import TCPConnector
 from aiohttp.resolver import DefaultResolver
 
-__all__ = 'ClientSession', 'DNSOverHTTPSResolver', 'RecordType'
+__all__ = 'DNSOverHTTPSClientSession', 'DNSOverHTTPSResolver', 'RecordType'
 
 
 class RecordType(enum.Enum):
@@ -22,13 +22,7 @@ class RecordType(enum.Enum):
 class DNSOverHTTPSResolver(AbstractResolver):
     """DNS over HTTPS Resolver"""
 
-    def __init__(
-        self,
-        *,
-        endpoints: List[str],
-        json_loads=json.loads,
-        resolver_class=None,
-    ) -> None:
+    def __init__(self, *, endpoints: List[str], json_loads=json.loads, resolver_class=None) -> None:
         self.endpoints = endpoints
         self.json_loads = json_loads
         if resolver_class is None:
@@ -42,15 +36,14 @@ async def _resolve(self, endpoint: str, host, port, family):
             record_type = RecordType.A
 
         params = {
-            'ct': 'application/dns-json',
             'name': host,
             'type': record_type.name,
         }
 
         resolver = self.resolveer_class()
         connector = TCPConnector(resolver=resolver)
-    
-        async with CS(connector=connector) as session:
+
+        async with CS(connector=connector, headers={"accept": "application/dns-json"}) as session:
             async with session.get(endpoint, params=params) as resp:
                 data = self.json_loads(await resp.text())
 
@@ -79,19 +72,15 @@ async def resolve(self, host, port=0, family=socket.AF_INET):
             self._resolve(endpoint, host, port, family)
             for endpoint in self.endpoints
         ]
-        done, pending = await asyncio.wait(
-            tasks,
-            return_when=asyncio.FIRST_COMPLETED,
-        )
-        for p in pending:
-            p.cancel()
-        return list(done)[0].result()
+        done = await asyncio.gather(*tasks)
+        return done[0]
 
     async def close(self):
         pass
 
 
-def ClientSession(*args, **kwargs) -> CS:  # noqa
+# noinspection PyTypeChecker
+def DNSOverHTTPSClientSession(*args, **kwargs) -> CS:  # noqa
     """Shortcut of aiohttp.ClientSession and DNSOverHTTPSResolver"""
 
     endpoints = kwargs.pop(
diff --git a/tests/test_aiohttp_doh.py b/tests/test_aiohttp_doh.py
new file mode 100644
index 0000000..a0d1fec
--- /dev/null
+++ b/tests/test_aiohttp_doh.py
@@ -0,0 +1,27 @@
+import pytest
+from aiohttp import ClientSession, TCPConnector
+
+import aiohttp_doh
+from aiohttp_doh import DNSOverHTTPSClientSession
+
+pytest_plugins = ('pytest_asyncio',)
+
+
+@pytest.mark.asyncio
+async def test_DNSOverHTTPSResolver():
+    endpoints = [
+        'https://dns.google.com/resolve',
+        'https://cloudflare-dns.com/dns-query',
+    ]
+    resolver = aiohttp_doh.DNSOverHTTPSResolver(endpoints=endpoints)
+    connector = TCPConnector(resolver=resolver)
+    async with ClientSession(connector=connector) as session:
+        async with session.head("https://example.com") as response:
+            assert response.status == 200
+
+
+@pytest.mark.asyncio
+async def test_DNSOverHTTPSClientSession():
+    async with DNSOverHTTPSClientSession() as session:
+        async with session.head("https://example.com") as response:
+            assert response.status == 200