diff --git a/base-notebook/test/test_container_options.py b/base-notebook/test/test_container_options.py
index b21bf7b4..65e85d24 100644
--- a/base-notebook/test/test_container_options.py
+++ b/base-notebook/test/test_container_options.py
@@ -20,7 +20,7 @@ def test_cli_args(container: TrackedContainer, http_client: requests.Session) ->
         ports={"8888/tcp": None},
     )
     host_port = container.get_host_port("8888/tcp")
-    resp = http_client.get("http://localhost:" + host_port)
+    resp = http_client.get(f"http://localhost:{host_port}")
     resp.raise_for_status()
     logs = running_container.logs().decode("utf-8")
     LOGGER.debug(logs)
@@ -47,7 +47,7 @@ def test_unsigned_ssl(
     # abort the retry logic. Forcing a long sleep for the moment until I have
     # time to dig more.
     time.sleep(5)
-    resp = http_client.get("https://localhost:" + host_port, verify=False)
+    resp = http_client.get(f"https://localhost:{host_port}", verify=False)
     resp.raise_for_status()
     assert "login_submit" in resp.text
     logs = running_container.logs().decode("utf-8")
diff --git a/base-notebook/test/test_start_container.py b/base-notebook/test/test_start_container.py
index e72988be..7d9b30f9 100644
--- a/base-notebook/test/test_start_container.py
+++ b/base-notebook/test/test_start_container.py
@@ -70,7 +70,7 @@ def test_start_notebook(
     # checking if the server is listening
     if expected_start:
         host_port = container.get_host_port("8888/tcp")
-        resp = http_client.get("http://localhost:" + host_port)
+        resp = http_client.get(f"http://localhost:{host_port}")
         assert resp.status_code == 200, "Server is not listening"
 
 
diff --git a/conftest.py b/conftest.py
index 5f57ff3f..a0026265 100644
--- a/conftest.py
+++ b/conftest.py
@@ -109,6 +109,7 @@ class TrackedContainer:
         return logs
 
     def get_host_port(self, container_port: str) -> str:
+        """Returns the host port associated with the tracked container's port."""
         assert isinstance(self.container, Container)
         self.container.reload()
         return self.container.attrs["NetworkSettings"]["Ports"][container_port][0][
diff --git a/test/test_notebook.py b/test/test_notebook.py
index 390649ec..163e1ecd 100644
--- a/test/test_notebook.py
+++ b/test/test_notebook.py
@@ -12,6 +12,6 @@ def test_secured_server(
     """Notebook server should eventually request user login."""
     container.run_detached(ports={"8888/tcp": None})
     host_port = container.get_host_port("8888/tcp")
-    resp = http_client.get("http://localhost:" + host_port)
+    resp = http_client.get(f"http://localhost:{host_port}")
     resp.raise_for_status()
     assert "login_submit" in resp.text, "User login not requested"