diff --git a/eventsourcingdb/client.py b/eventsourcingdb/client.py
index ad16525..c197a21 100644
--- a/eventsourcingdb/client.py
+++ b/eventsourcingdb/client.py
@@ -45,12 +45,6 @@ async def __aexit__(
     ) -> None:
         await self.__http_client.__aexit__(exc_type, exc_val, exc_tb)
 
-    async def initialize(self) -> None:
-        await self.__http_client.initialize()
-
-    async def close(self) -> None:
-        await self.__http_client.close()
-
     @property
     def http_client(self) -> HttpClient:
         return self.__http_client
diff --git a/eventsourcingdb/http_client/http_client.py b/eventsourcingdb/http_client/http_client.py
index 14a890a..548563a 100644
--- a/eventsourcingdb/http_client/http_client.py
+++ b/eventsourcingdb/http_client/http_client.py
@@ -3,8 +3,6 @@
 import aiohttp
 from aiohttp import ClientSession
 
-from ..errors.custom_error import CustomError
-
 from .get_get_headers import get_get_headers
 from .get_post_headers import get_post_headers
 from .response import Response
@@ -21,7 +19,7 @@ def __init__(
         self.__session: ClientSession | None = None
 
     async def __aenter__(self) -> 'HttpClient':
-        await self.initialize()
+        await self.__initialize()
         return self
 
     async def __aexit__(
@@ -30,12 +28,16 @@ async def __aexit__(
         exc_val: BaseException | None = None,
         exc_tb: TracebackType | None = None,
     ) -> None:
-        await self.close()
+        await self.__close()
+
+    async def __initialize(self) -> None:
+        # If a session already exists, close it first to prevent leaks
+        if self.__session is not None:
+            await self.__session.close()
 
-    async def initialize(self) -> None:
-        self.__session = aiohttp.ClientSession()
+        self.__session = aiohttp.ClientSession(connector_owner=True)
 
-    async def close(self) -> None:
+    async def __close(self) -> None:
         if self.__session is not None:
             await self.__session.close()
             self.__session = None
@@ -49,7 +51,7 @@ def join_segments(first: str, *rest: str) -> str:
 
     async def post(self, path: str, request_body: str) -> Response:
         if self.__session is None:
-            await self.initialize()
+            await self.__initialize()
 
         url_path = HttpClient.join_segments(self.__base_url, path)
         headers = get_post_headers(self.__api_token)
@@ -70,8 +72,7 @@ async def get(
         with_authorization: bool = True,
     ) -> Response:
         if self.__session is None:
-            raise CustomError(
-                "HTTP client session not initialized. Call initialize() before making requests.")
+            await self.__initialize()
 
         async def __request_executor() -> Response:
             url_path = HttpClient.join_segments(self.__base_url, path)
diff --git a/tests/shared/database.py b/tests/shared/database.py
index 552748b..7576caa 100644
--- a/tests/shared/database.py
+++ b/tests/shared/database.py
@@ -35,14 +35,10 @@ def _create_container(cls, api_token, image_tag) -> Container:
     @staticmethod
     async def _initialize_clients(container, api_token) -> tuple[Client, Client]:
         with_authorization_client = container.get_client()
-        await with_authorization_client.initialize()
-
         with_invalid_url_client = Client(
             base_url='http://localhost.invalid',
             api_token=api_token
         )
-        await with_invalid_url_client.initialize()
-
         return with_authorization_client, with_invalid_url_client
 
     @classmethod
@@ -111,6 +107,17 @@ def get_client(self, client_type: str = CLIENT_TYPE_WITH_AUTH) -> Client:
 
         raise ValueError(f'Unknown client type: {client_type}')
 
+    async def __aenter__(self) -> 'Database':
+        return self
+
+    async def __aexit__(
+        self,
+        exc_type: type[BaseException] | None = None,
+        exc_val: BaseException | None = None,
+        exc_tb: object | None = None
+    ) -> None:
+        await self.stop()
+
     def get_base_url(self) -> str:
         return self.__container.get_base_url()
 
@@ -118,5 +125,18 @@ def get_api_token(self) -> str:
         return self.__container.get_api_token()
 
     async def stop(self) -> None:
+        if self.__with_authorization_client:
+            try:
+                await self.__with_authorization_client.__aexit__(None, None, None)
+            except (ConnectionError) as e:
+                logging.warning("Error closing authorization client: %s", e)
+
+        if self.__with_invalid_url_client:
+            try:
+                await self.__with_invalid_url_client.__aexit__(None, None, None)
+            except (ConnectionError) as e:
+                logging.warning("Error closing invalid URL client: %s", e)
+
+        # Then stop the container
         if (container := getattr(self.__class__, '_Database__container', None)):
             container.stop()
diff --git a/tests/shared/start_local_http_server.py b/tests/shared/start_local_http_server.py
index d2f3611..db8ca19 100644
--- a/tests/shared/start_local_http_server.py
+++ b/tests/shared/start_local_http_server.py
@@ -73,6 +73,4 @@ def stop_server() -> None:
         f'http://localhost:{local_http_server.port}',
         'access-token',
     )
-    await client.initialize()
-
     return client, stop_server