diff --git a/aiven/client/client.py b/aiven/client/client.py
index 2c6d408..300bb00 100644
--- a/aiven/client/client.py
+++ b/aiven/client/client.py
@@ -175,7 +175,7 @@ def verify(
                 time.sleep(0.2)
 
         # Check API is actually returning data or not
-        if response.status_code == HTTPStatus.NO_CONTENT or response.headers.get("Content-Length", "0") == "0":
+        if response.status_code == HTTPStatus.NO_CONTENT or len(response.content) == 0:
             return {}
 
         result = response.json()
diff --git a/tests/test_cli.py b/tests/test_cli.py
index ec52239..fafaef4 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -157,7 +157,7 @@ def test_service_user_create() -> None:
 def test_service_topic_create(command_line: str, expected_post_data: Mapping[str, str | int | None]) -> None:
     client = AivenClient("")
     session = MagicMock(spec=Session)
-    session.post.return_value = MagicMock(status_code=200, json=MagicMock(return_value={}))
+    session.post.return_value = MagicMock(status_code=200, json=MagicMock(return_value={}), content=b"{}", reason="OK")
     client.session = session
     cli = build_aiven_cli(client)
     assert cli.run(args=command_line.split(" ")) is None
@@ -258,7 +258,9 @@ def get_service_topic(self, project: str, service: str, topic: str) -> Mapping:
 
     client = TestAivenClient()
     session = MagicMock(spec=Session)
-    session.put.return_value = MagicMock(status_code=200, json=MagicMock(return_value={"message": "updated"}))
+    session.put.return_value = MagicMock(
+        status_code=200, json=MagicMock(return_value={"message": "updated"}), content=b'{"message":"updated"}', reason="OK"
+    )
     client.session = session
     cli = build_aiven_cli(client)
     assert cli.run(args=command_line.split(" ")) is None
diff --git a/tests/test_client.py b/tests/test_client.py
index 819cd5a..90c9140 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -9,6 +9,7 @@
 from typing import Any
 from unittest import mock
 
+import json
 import pytest
 
 
@@ -16,6 +17,10 @@ class MockResponse:
     def __init__(self, status_code: int, json_data: dict[str, Any] | None = None, headers: dict[str, str] | None = None):
         self.status_code = status_code
         self.json_data = json_data
+        if json_data is not None:
+            self.content = json.dumps(json_data).encode("utf-8")
+        else:
+            self.content = b""
         self.headers = {} if headers is None else headers
 
     def json(self) -> Any:
@@ -26,7 +31,7 @@ def json(self) -> Any:
     "response",
     [
         MockResponse(status_code=HTTPStatus.NO_CONTENT),
-        MockResponse(status_code=HTTPStatus.CREATED, headers={"Content-Length": "0"}),
+        MockResponse(status_code=HTTPStatus.CREATED),
     ],
 )
 def test_no_content_returned_from_api(response: MockResponse) -> None: