test: example use sqlite3 as unittest backend

[asukaminato0721]

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Summary

at least better than mock session.

#37827

Screenshots

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Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran make lint && make type-check (backend) and cd web && pnpm exec vp staged (frontend) to appease the lint gods

[github-actions]

Pyrefly Diff

base → PR

--- /tmp/pyrefly_base.txt	2026-06-29 08:46:45.497837439 +0000
+++ /tmp/pyrefly_pr.txt	2026-06-29 08:46:31.291752268 +0000
@@ -6907,6 +6907,8 @@
    --> tests/unit_tests/services/retention/workflow_run/test_restore_archived_workflow_run.py:760:71
 ERROR `in` is not supported between `Literal['not found']` and `None` [not-iterable]
    --> tests/unit_tests/services/retention/workflow_run/test_restore_archived_workflow_run.py:907:16
+ERROR Object of class `FromClause` has no attribute `create` [missing-attribute]
+  --> tests/unit_tests/services/test_account_service.py:27:5
 ERROR Argument `_FakeWriteSession` is not assignable to parameter `session` with type `scoped_session[Unknown]` in function `services.agent_app_feature_service.AgentAppFeatureConfigService.update_features` [bad-argument-type]
    --> tests/unit_tests/services/test_agent_app_feature_service.py:102:21
 ERROR Object of class `FromClause` has no attribute `create` [missing-attribute]

[github-actions]

Pyrefly Type Coverage

Metric	Base	PR	Delta
Type coverage	51.49%	51.50%	+0.00%
Strict coverage	51.01%	51.01%	+0.00%
Typed symbols	30,844	30,847	+3
Untyped symbols	29,331	29,331	0
Modules	2931	2931	0