Add regression test for DeleteAnalysisMutation return value

Address PR #1369 review (Claude bot): the missing-return fix in
config/graphql/analysis_mutations.py — restoring
`return DeleteAnalysisMutation(ok=True, message="SUCCESS")` — was the
most impactful behavioral fix bundled into the type-annotation pass,
but no regression test pinned the success shape.

The new test grants DELETE permission on an Analysis to its creator,
runs the GraphQL mutation, and asserts the response contains
`ok=True`/`message="SUCCESS"` rather than the `null` payload that was
previously returned. Without the restored `return`, the assertion on
`data.deleteAnalysis` being non-null fails immediately.

Author: JSv4

opencontractserver/tests/test_delete_analysis_mutation.py

@@ -0,0 +1,97 @@
+"""Regression coverage for the DeleteAnalysisMutation return value.
+
+PR #1369 restored the missing ``return DeleteAnalysisMutation(...)`` line in
+``config/graphql/analysis_mutations.py``. Before the fix the mutation kicked
+off the async deletion task correctly but returned ``None`` to the GraphQL
+client, so the frontend never observed ``ok=True`` / a success message.
+"""
+
+from __future__ import annotations
+
+import logging
+
+import factory
+from django.contrib.auth import get_user_model
+from django.db import transaction
+from django.db.models.signals import post_save
+from django.test import TestCase
+from graphql_relay import to_global_id
+
+from config.graphql.schema import schema
+from opencontractserver.analyzer.models import Analysis, Analyzer, GremlinEngine
+from opencontractserver.types.enums import PermissionTypes
+from opencontractserver.utils.permissioning import set_permissions_for_obj_to_user
+
+User = get_user_model()
+logger = logging.getLogger(__name__)
+
+
+class _Context:
+    def __init__(self, user):
+        self.user = user
+
+
+class DeleteAnalysisMutationReturnValueTestCase(TestCase):
+    """Pin the success-shape returned by ``DeleteAnalysisMutation.mutate``."""
+
+    DELETE_ANALYSIS = """
+        mutation ($id: String!) {
+            deleteAnalysis(id: $id) {
+                ok
+                message
+            }
+        }
+    """
+
+    @factory.django.mute_signals(post_save)
+    def setUp(self) -> None:
+        with transaction.atomic():
+            self.user = User.objects.create_user(
+                username="alice",
+                password="abcd1234",
+            )
+
+            self.gremlin = GremlinEngine.objects.create(
+                url="http://example.invalid/gremlin",
+                creator=self.user,
+            )
+            self.analyzer = Analyzer.objects.create(
+                id="test-analyzer",
+                description="Test analyzer for delete mutation",
+                creator=self.user,
+                host_gremlin=self.gremlin,
+            )
+            self.analysis = Analysis.objects.create(
+                analyzer=self.analyzer,
+                creator=self.user,
+            )
+
+        # The owner has CRUD via the post-creation signal in production, but
+        # signals are muted in setUp so we grant DELETE explicitly here.
+        set_permissions_for_obj_to_user(
+            user_val=self.user,
+            instance=self.analysis,
+            permissions=[PermissionTypes.DELETE],
+        )
+
+    def test_mutation_returns_ok_and_success_message(self) -> None:
+        from graphene.test import Client
+
+        client = Client(schema, context_value=_Context(self.user))
+
+        response = client.execute(
+            self.DELETE_ANALYSIS,
+            variable_values={
+                "id": to_global_id("AnalysisType", self.analysis.id),
+            },
+        )
+
+        # Without the restored return statement, ``response["data"]`` would
+        # contain ``{"deleteAnalysis": null}`` and this assertion fails.
+        self.assertIsNone(response.get("errors"))
+        self.assertIsNotNone(response["data"]["deleteAnalysis"])
+        self.assertTrue(response["data"]["deleteAnalysis"]["ok"])
+        self.assertEqual(
+            response["data"]["deleteAnalysis"]["message"],
+            "SUCCESS",
+        )