feat: ensure notebook endpoints do their job (#388)

This work brings the notebook related endpoints to a working state
to serve as replacement for the renku-notebooks external service.

Short summary:
- API tests have been added
- Code has been fixed to answer / handle exception
- Automated test cluster creation has been added using k3d

---------

Co-authored-by: Tasko Olevski <[email protected]>

Author: sgaist

components/renku_data_services/notebooks/api/classes/k8s_client.py

@@ -449,7 +449,7 @@ async def get_server_logs(
         server = await self.get_server(server_name, safe_username)
         if not server:
             raise errors.MissingResourceError(
-                message=f"Cannot find server {server_name} for user " f"{safe_username} to retrieve logs."
+                message=f"Cannot find server {server_name} for user {safe_username} to retrieve logs."
             )
         pod_name = f"{server_name}-0"
         return await self.renku_ns_client.get_pod_logs(pod_name, max_log_lines)
@@ -490,9 +490,10 @@ async def delete_server(self, server_name: str, safe_username: str) -> None:
         """Delete the server."""
         server = await self.get_server(server_name, safe_username)
         if not server:
-            return None
-        await self.renku_ns_client.delete_server(server_name)
-        return None
+            raise MissingResourceError(
+                f"Cannot find server {server_name} for user " f"{safe_username} in order to delete it."
+            )
+        return await self.renku_ns_client.delete_server(server_name)
 
     async def patch_tokens(self, server_name: str, renku_tokens: RenkuTokens, gitlab_token: GitlabToken) -> None:
         """Patch the Renku and Gitlab access tokens used in a session."""

test/bases/renku_data_services/data_api/test_sessions.py

@@ -1,5 +1,7 @@
 """Tests for sessions blueprints."""
 
+import os
+import shutil
 from asyncio import AbstractEventLoop
 from typing import Any
 
@@ -11,6 +13,21 @@
 from renku_data_services.crc.apispec import ResourcePool
 from renku_data_services.users.models import UserInfo
 
+from .utils import K3DCluster, setup_amalthea
+
+os.environ["KUBECONFIG"] = ".k3d-config.yaml"
+
+
+@pytest.fixture(scope="module", autouse=True)
+def cluster() -> K3DCluster:
+    if shutil.which("k3d") is None:
+        pytest.skip("Requires k3d for cluster creation")
+
+    with K3DCluster("renku-test-session") as cluster:
+        setup_amalthea("amalthea-se", "amalthea-sessions", "0.0.10-new-operator-chart", cluster)
+
+        yield cluster
+
 
 @pytest.fixture
 def create_session_environment(sanic_client: SanicASGITestClient, admin_headers):