From 32cd7c1077c9bf8b4294ae2b5d51d4c001d14387 Mon Sep 17 00:00:00 2001
From: parththakkar106 <f20200088@pilani.bits-pilani.ac.in>
Date: Sat, 29 Aug 2026 00:47:46 +0530
Subject: [PATCH] Give the tests one setup instead of thirty-five

Every test module carried the same eight-line prologue redirecting the
database to a temp file. Only the first one to be imported ever took
effect: `app.database` reads `AIDND_DB_PATH` at import and builds `engine`
from it once, so by the time the second module ran the engine already
existed. The other 34 copies created a temp file that nothing opened and
nothing deleted, and leaked one per module per run.

`conftest.py` now does it once, which is early enough because pytest
imports conftest before any test module. It also deletes the file when the
run ends. The tests still share one database, exactly as they already did:
each `client` fixture calls `create_all` on setup and `drop_all` on
teardown, so no test sees another test's rows.

`tests/fakes.py` holds the one `ScriptedProvider`. Nine modules each had a
copy, and the copies had drifted into four feature sets, so a test that
needed to raise a provider error had to be written in one of the files
whose copy supported that. The shared one is the superset. The two
`FakeProvider` copies were the same class with a fixed reply, so they use
it too. `test_chat.py` keeps its own, which implements `chat` rather than
`generate` and records what it was constructed with.

An autouse fixture resets the fake's class state between tests, so a stale
reply list can no longer reach the next test.

435 lines out of the suite. 549 tests pass. Verified live by sabotage:
breaking the shared fake fails 13 tests across four modules.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014Dix4oGV3njgWRdu7P9t6r
---
 backend/tests/conftest.py                    | 57 ++++++++++++++++++++
 backend/tests/fakes.py                       | 41 ++++++++++++++
 backend/tests/test_accesslog.py              |  9 ----
 backend/tests/test_action_paging.py          |  9 ----
 backend/tests/test_analytics.py              |  9 ----
 backend/tests/test_attempt_siblings.py       | 28 +---------
 backend/tests/test_branch_clause.py          |  9 ----
 backend/tests/test_branch_forking.py         | 28 +---------
 backend/tests/test_branch_management.py      | 24 +--------
 backend/tests/test_bundle_v2.py              | 26 +--------
 backend/tests/test_chat.py                   |  9 ----
 backend/tests/test_egress.py                 |  9 ----
 backend/tests/test_embedding_blob.py         |  7 ---
 backend/tests/test_embedding_model_switch.py |  9 ----
 backend/tests/test_guest_cleanup.py          |  7 ---
 backend/tests/test_history_window.py         |  9 ----
 backend/tests/test_length_hint.py            |  7 ---
 backend/tests/test_memory_nodes.py           |  9 ----
 backend/tests/test_memory_retrieval.py       |  9 ----
 backend/tests/test_memory_settling.py        |  7 ---
 backend/tests/test_netguard.py               |  9 ----
 backend/tests/test_prompt_caching.py         |  6 ---
 backend/tests/test_ratelimit_hardening.py    |  9 ----
 backend/tests/test_retry_variants.py         | 33 ++----------
 backend/tests/test_scenario_art.py           |  7 ---
 backend/tests/test_scenario_refresh.py       |  9 ----
 backend/tests/test_seed_sweep.py             |  7 ---
 backend/tests/test_snapshot_compression.py   |  7 ---
 backend/tests/test_starter_adventure.py      |  7 ---
 backend/tests/test_state_revert.py           |  7 ---
 backend/tests/test_story_tree_baseline.py    | 33 +-----------
 backend/tests/test_take_edit.py              | 24 +--------
 backend/tests/test_take_parentage.py         | 22 +-------
 backend/tests/test_take_state.py             | 26 +--------
 backend/tests/test_tree_migration.py         |  7 ---
 backend/tests/test_turn_flow_integration.py  | 24 ++-------
 backend/tests/test_worldstate_integration.py | 24 ++-------
 37 files changed, 123 insertions(+), 460 deletions(-)
 create mode 100644 backend/tests/conftest.py
 create mode 100644 backend/tests/fakes.py

diff --git a/backend/tests/conftest.py b/backend/tests/conftest.py
new file mode 100644
index 0000000..b63f213
--- /dev/null
+++ b/backend/tests/conftest.py
@@ -0,0 +1,57 @@
+"""Shared setup for the test suite.
+
+pytest imports this file before it imports any test module, which is the only
+reason the database redirection below works. `app.database` reads
+`AIDND_DB_PATH` at import and builds `engine` from it once, so the variable has
+to be set before the first `from app...` line anywhere in the suite.
+
+Every test module used to carry its own copy of that redirection. Only the first
+one to be imported ever took effect, because the engine already existed by the
+time the second one ran. The other copies created a temp file that nothing
+opened and nothing deleted. One copy here does the job, and it cleans up after
+itself.
+
+The tests share one database. That is not new: they already did. Each `client`
+fixture calls `Base.metadata.create_all` on setup and `drop_all` on teardown, so
+no test sees another test's rows.
+"""
+import os
+import tempfile
+
+_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
+_tmp.close()
+os.environ["AIDND_DB_PATH"] = _tmp.name
+# A real `AIDND_DATABASE_URL` or `DATABASE_URL` in the developer's shell points
+# at Postgres, and `app.database` prefers either over the SQLite path above.
+# Clear both, so running the suite never touches a server database.
+os.environ.pop("AIDND_DATABASE_URL", None)
+os.environ.pop("DATABASE_URL", None)
+
+import pytest  # noqa: E402  Import order is load-bearing; see above.
+
+from fakes import ScriptedProvider  # noqa: E402
+
+
+@pytest.fixture(autouse=True)
+def reset_scripted_provider():
+    """Clears the fake provider's state between tests.
+
+    `ScriptedProvider` keeps its replies and its call count on the class, because
+    the code under test constructs the provider itself and a test cannot reach
+    the instance. Class state outlives a test, so reset it here rather than
+    trusting every fixture to remember.
+    """
+    ScriptedProvider.replies = []
+    ScriptedProvider.calls = 0
+    ScriptedProvider.prompts = []
+    yield
+
+
+def pytest_sessionfinish(session, exitstatus):
+    """Deletes the temporary database once the run ends."""
+    try:
+        os.unlink(_tmp.name)
+    except OSError:
+        # The file is already gone, or Windows still holds a handle on it. It is
+        # in the temp directory either way, so leaving it costs nothing.
+        pass
diff --git a/backend/tests/fakes.py b/backend/tests/fakes.py
new file mode 100644
index 0000000..8b035c9
--- /dev/null
+++ b/backend/tests/fakes.py
@@ -0,0 +1,41 @@
+"""Stand-ins for the parts of the app a test must not really call.
+
+Import these rather than writing another copy. Nine test modules each carried
+their own `ScriptedProvider`, and the copies had drifted into four different
+feature sets, so a test that needed to raise a provider error had to be written
+in one of the files whose copy supported it.
+"""
+
+
+class ScriptedProvider:
+    """Streams canned replies in place of `OpenAICompatibleProvider`.
+
+    Set `replies` to the texts the model returns, one per call. The last entry
+    repeats once the list runs out, so a test that plays more turns than it
+    scripted still gets text. To drive the provider-error path, put an
+    `Exception` in the list. It is raised rather than streamed.
+
+    State lives on the class, not on the instance, because the turn engine
+    constructs the provider itself and a test never sees the object. The autouse
+    `reset_scripted_provider` fixture in `conftest.py` clears it between tests.
+
+    `prompts` records every assembled `(system, story)` pair, which is what a
+    test asserts on to check what the model was shown.
+    """
+
+    last_usage = None
+    replies: list = []
+    calls = 0
+    prompts: list = []
+
+    def __init__(self, *a, **k):
+        pass
+
+    async def generate(self, parts, *, temperature, max_tokens):
+        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
+        ScriptedProvider.calls += 1
+        ScriptedProvider.prompts.append((parts.system, parts.story))
+        reply = ScriptedProvider.replies[index]
+        if isinstance(reply, Exception):
+            raise reply
+        yield ("text", reply)
diff --git a/backend/tests/test_accesslog.py b/backend/tests/test_accesslog.py
index d014974..5a1da0c 100644
--- a/backend/tests/test_accesslog.py
+++ b/backend/tests/test_accesslog.py
@@ -9,15 +9,6 @@ accounts on a schedule, and a log that deletes itself is not a log.
 
     python -m pytest tests/test_accesslog.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
diff --git a/backend/tests/test_action_paging.py b/backend/tests/test_action_paging.py
index 6f4280a..4c09d7c 100644
--- a/backend/tests/test_action_paging.py
+++ b/backend/tests/test_action_paging.py
@@ -12,15 +12,6 @@ to be scrolling. An anchor means the same thing before and after.
 
     python -m pytest tests/test_action_paging.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
diff --git a/backend/tests/test_analytics.py b/backend/tests/test_analytics.py
index e8765c4..f0e3eb4 100644
--- a/backend/tests/test_analytics.py
+++ b/backend/tests/test_analytics.py
@@ -9,15 +9,6 @@ the dashboard, and cannot inflate what it reports beyond hitting the page.
 
     python -m pytest tests/test_analytics.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 from datetime import timedelta
 
 import pytest
diff --git a/backend/tests/test_attempt_siblings.py b/backend/tests/test_attempt_siblings.py
index dbe0252..2afbbb8 100644
--- a/backend/tests/test_attempt_siblings.py
+++ b/backend/tests/test_attempt_siblings.py
@@ -8,15 +8,6 @@ story, and the arrangement costs neither an extra prompt nor an extra turn.
 
     python -m pytest tests/test_attempt_siblings.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
@@ -26,9 +17,10 @@ from app import attempts, auth, limits, models, tree
 from app.context import cursors, history
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts
 from app.routers import adventures
 
+from fakes import ScriptedProvider
+
 SCHEMA = {"player": {"hp": {"min": 0, "max": 100, "initial": 100}}}
 
 GOLD_SCRIPT = """
@@ -40,22 +32,6 @@ modifier(text);
 """
 
 
-class ScriptedProvider:
-    last_usage = None
-    replies: list = []
-    calls = 0
-    prompts: list = []
-
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
-        ScriptedProvider.calls += 1
-        ScriptedProvider.prompts.append((parts.system, parts.story))
-        yield ("text", ScriptedProvider.replies[index])
-
-
 @pytest.fixture()
 def client(monkeypatch):
     Base.metadata.create_all(bind=engine)
diff --git a/backend/tests/test_branch_clause.py b/backend/tests/test_branch_clause.py
index cf84fdf..6e52fd5 100644
--- a/backend/tests/test_branch_clause.py
+++ b/backend/tests/test_branch_clause.py
@@ -21,15 +21,6 @@ nodes may appear on C.
 
     python -m pytest tests/test_branch_clause.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
diff --git a/backend/tests/test_branch_forking.py b/backend/tests/test_branch_forking.py
index 41cac9b..9fb1181 100644
--- a/backend/tests/test_branch_forking.py
+++ b/backend/tests/test_branch_forking.py
@@ -12,15 +12,6 @@ that makes borrowing possible lives in `lineage`.
 
     python -m pytest tests/test_branch_forking.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
@@ -29,9 +20,10 @@ from app import auth, limits, models
 from app.context import cursors, lineage
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts
 from app.routers import adventures
 
+from fakes import ScriptedProvider
+
 # `hp` moves freely. `mana` has a cooldown of 2 turns, so an incorrect
 # advance shows up as a change the referee should have rejected.
 SCHEMA = {
@@ -50,22 +42,6 @@ modifier(text);
 """
 
 
-class ScriptedProvider:
-    last_usage = None
-    replies: list = []
-    calls = 0
-    prompts: list = []
-
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
-        ScriptedProvider.calls += 1
-        ScriptedProvider.prompts.append((parts.system, parts.story))
-        yield ("text", ScriptedProvider.replies[index])
-
-
 @pytest.fixture()
 def client(monkeypatch):
     Base.metadata.create_all(bind=engine)
diff --git a/backend/tests/test_branch_management.py b/backend/tests/test_branch_management.py
index 27023ea..5c1f0b0 100644
--- a/backend/tests/test_branch_management.py
+++ b/backend/tests/test_branch_management.py
@@ -19,15 +19,6 @@ Two rules carry most of this file:
 
     python -m pytest tests/test_branch_management.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
@@ -37,22 +28,9 @@ from app import auth, limits, models, schemas
 from app.context import cursors, lineage
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts
 from app.routers import adventures
 
-
-class ScriptedProvider:
-    last_usage = None
-    replies: list = []
-    calls = 0
-
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
-        ScriptedProvider.calls += 1
-        yield ("text", ScriptedProvider.replies[index])
+from fakes import ScriptedProvider
 
 
 @pytest.fixture()
diff --git a/backend/tests/test_bundle_v2.py b/backend/tests/test_bundle_v2.py
index cb2ff28..e3c0682 100644
--- a/backend/tests/test_bundle_v2.py
+++ b/backend/tests/test_bundle_v2.py
@@ -23,15 +23,6 @@ importer a file that does disagree with itself.
 
     python -m pytest tests/test_bundle_v2.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
@@ -40,9 +31,10 @@ from app import auth, bundle, limits, models
 from app.context import lineage
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts
 from app.routers import adventures
 
+from fakes import ScriptedProvider
+
 SCHEMA = {"player": {"hp": {"min": 0, "max": 100, "initial": 100}}}
 
 # Ten gold a turn, so the stored gold total tells how many turns the
@@ -58,20 +50,6 @@ modifier(text);
 OPENING = "You enter a cave."
 
 
-class ScriptedProvider:
-    last_usage = None
-    replies: list = []
-    calls = 0
-
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
-        ScriptedProvider.calls += 1
-        yield ("text", ScriptedProvider.replies[index])
-
-
 @pytest.fixture()
 def client(monkeypatch):
     Base.metadata.create_all(bind=engine)
diff --git a/backend/tests/test_chat.py b/backend/tests/test_chat.py
index df52166..42acfce 100644
--- a/backend/tests/test_chat.py
+++ b/backend/tests/test_chat.py
@@ -6,15 +6,6 @@ page.
 
     python -m pytest tests/test_chat.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
diff --git a/backend/tests/test_egress.py b/backend/tests/test_egress.py
index 64cf5b5..372f72e 100644
--- a/backend/tests/test_egress.py
+++ b/backend/tests/test_egress.py
@@ -17,15 +17,6 @@ Two kinds of guard live here, and both are needed:
 
     python -m pytest tests/test_egress.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import json
 import random
 
diff --git a/backend/tests/test_embedding_blob.py b/backend/tests/test_embedding_blob.py
index c45a2c0..6fa82a5 100644
--- a/backend/tests/test_embedding_blob.py
+++ b/backend/tests/test_embedding_blob.py
@@ -7,15 +7,8 @@ for bit, and that the migration reaches every row, however many there are.
 
     python -m pytest tests/test_embedding_blob.py -v
 """
-import os
 import struct
-import tempfile
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import json
 import random
diff --git a/backend/tests/test_embedding_model_switch.py b/backend/tests/test_embedding_model_switch.py
index 4e3db33..292d62d 100644
--- a/backend/tests/test_embedding_model_switch.py
+++ b/backend/tests/test_embedding_model_switch.py
@@ -19,15 +19,6 @@ garbage instead.
 
     python -m pytest tests/test_embedding_model_switch.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import asyncio
 
 import pytest
diff --git a/backend/tests/test_guest_cleanup.py b/backend/tests/test_guest_cleanup.py
index 995ba57..5f180d4 100644
--- a/backend/tests/test_guest_cleanup.py
+++ b/backend/tests/test_guest_cleanup.py
@@ -6,15 +6,8 @@ deleted.
 
     python -m pytest tests/test_guest_cleanup.py -v
 """
-import os
-import tempfile
 from datetime import timedelta
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 from sqlalchemy import create_engine, event
diff --git a/backend/tests/test_history_window.py b/backend/tests/test_history_window.py
index d0a5635..54972c0 100644
--- a/backend/tests/test_history_window.py
+++ b/backend/tests/test_history_window.py
@@ -16,15 +16,6 @@ Two things must hold, and both are easy to break by accident:
 
     python -m pytest tests/test_history_window.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from sqlalchemy import event
 
diff --git a/backend/tests/test_length_hint.py b/backend/tests/test_length_hint.py
index 7477e29..0c26659 100644
--- a/backend/tests/test_length_hint.py
+++ b/backend/tests/test_length_hint.py
@@ -16,15 +16,8 @@ Two things are easy to break here:
 
     python -m pytest tests/test_length_hint.py -v
 """
-import os
 import re
-import tempfile
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 
diff --git a/backend/tests/test_memory_nodes.py b/backend/tests/test_memory_nodes.py
index e2fa158..2d6f24f 100644
--- a/backend/tests/test_memory_nodes.py
+++ b/backend/tests/test_memory_nodes.py
@@ -19,15 +19,6 @@ exactly as `test_branch_clause.py` builds it.
 
     python -m pytest tests/test_memory_nodes.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import asyncio
 
 import pytest
diff --git a/backend/tests/test_memory_retrieval.py b/backend/tests/test_memory_retrieval.py
index 110902d..98980f2 100644
--- a/backend/tests/test_memory_retrieval.py
+++ b/backend/tests/test_memory_retrieval.py
@@ -14,15 +14,6 @@ failure that no error message would report:
 
     python -m pytest tests/test_memory_retrieval.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import asyncio
 from datetime import timedelta
 
diff --git a/backend/tests/test_memory_settling.py b/backend/tests/test_memory_settling.py
index fa0fdb8..f339b7e 100644
--- a/backend/tests/test_memory_settling.py
+++ b/backend/tests/test_memory_settling.py
@@ -23,14 +23,7 @@ happened.
     python -m pytest tests/test_memory_settling.py -v
 """
 import asyncio
-import os
-import tempfile
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 
diff --git a/backend/tests/test_netguard.py b/backend/tests/test_netguard.py
index a0465f4..4b4e962 100644
--- a/backend/tests/test_netguard.py
+++ b/backend/tests/test_netguard.py
@@ -2,15 +2,6 @@
 
     python -m pytest tests/test_netguard.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 
 from app import auth, netguard
diff --git a/backend/tests/test_prompt_caching.py b/backend/tests/test_prompt_caching.py
index a84c0dd..88d51af 100644
--- a/backend/tests/test_prompt_caching.py
+++ b/backend/tests/test_prompt_caching.py
@@ -25,13 +25,7 @@ than assumed.
     python -m pytest tests/test_prompt_caching.py -v
 """
 import os
-import tempfile
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 
diff --git a/backend/tests/test_ratelimit_hardening.py b/backend/tests/test_ratelimit_hardening.py
index 60328e0..a83455f 100644
--- a/backend/tests/test_ratelimit_hardening.py
+++ b/backend/tests/test_ratelimit_hardening.py
@@ -9,15 +9,6 @@ also has an email-keyed throttle that no IP trick can weaken.
 
     python -m pytest tests/test_ratelimit_hardening.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 
 from app import auth, limits
diff --git a/backend/tests/test_retry_variants.py b/backend/tests/test_retry_variants.py
index 4623bbf..fad75c6 100644
--- a/backend/tests/test_retry_variants.py
+++ b/backend/tests/test_retry_variants.py
@@ -4,15 +4,6 @@ switchable, restoring the world/script state that attempt produced.
 
     python -m pytest tests/test_retry_variants.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
@@ -20,9 +11,11 @@ from fastapi.testclient import TestClient
 from app import auth, limits, models
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts, ProviderError
+from app.providers import ProviderError
 from app.routers import adventures
 
+from fakes import ScriptedProvider
+
 SCHEMA = {"player": {"hp": {"min": 0, "max": 100, "initial": 100}}}
 
 # Each turn spends 10 gold, so a double-applied or un-rolled-back attempt shows.
@@ -35,26 +28,6 @@ modifier(text);
 """
 
 
-class ScriptedProvider:
-    """Streams the next canned reply each call, so successive retries differ."""
-    last_usage = None
-    replies: list = []
-    calls = 0
-    prompts: list = []  # every assembled (system, story) pair, for context assertions
-
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
-        ScriptedProvider.calls += 1
-        ScriptedProvider.prompts.append((parts.system, parts.story))
-        reply = ScriptedProvider.replies[index]
-        if isinstance(reply, Exception):
-            raise reply
-        yield ("text", reply)
-
-
 @pytest.fixture()
 def client(monkeypatch):
     Base.metadata.create_all(bind=engine)
diff --git a/backend/tests/test_scenario_art.py b/backend/tests/test_scenario_art.py
index 44d8180..3d7e46c 100644
--- a/backend/tests/test_scenario_art.py
+++ b/backend/tests/test_scenario_art.py
@@ -9,14 +9,7 @@ player's last line.
     python -m pytest tests/test_scenario_art.py -v
 """
 import base64
-import os
-import tempfile
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 from fastapi import Depends
diff --git a/backend/tests/test_scenario_refresh.py b/backend/tests/test_scenario_refresh.py
index d5c0d73..9e37532 100644
--- a/backend/tests/test_scenario_refresh.py
+++ b/backend/tests/test_scenario_refresh.py
@@ -3,15 +3,6 @@ story cards and stat schema back down over a running adventure's copy.
 
     python -m pytest tests/test_scenario_refresh.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
diff --git a/backend/tests/test_seed_sweep.py b/backend/tests/test_seed_sweep.py
index c5affd0..0ff965d 100644
--- a/backend/tests/test_seed_sweep.py
+++ b/backend/tests/test_seed_sweep.py
@@ -8,14 +8,7 @@ deletes seeded rows no file claims any more.
     python -m pytest tests/test_seed_sweep.py -v
 """
 import json
-import os
-import tempfile
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 
diff --git a/backend/tests/test_snapshot_compression.py b/backend/tests/test_snapshot_compression.py
index 20e9fd9..26b8e23 100644
--- a/backend/tests/test_snapshot_compression.py
+++ b/backend/tests/test_snapshot_compression.py
@@ -17,16 +17,9 @@ Three things must hold, and only the first is obvious:
     python -m pytest tests/test_snapshot_compression.py -v
 """
 import json
-import os
 import random
-import tempfile
 import zlib
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 from sqlalchemy import text
diff --git a/backend/tests/test_starter_adventure.py b/backend/tests/test_starter_adventure.py
index 38e478a..3ca393e 100644
--- a/backend/tests/test_starter_adventure.py
+++ b/backend/tests/test_starter_adventure.py
@@ -8,14 +8,7 @@ empty account would.
     python -m pytest tests/test_starter_adventure.py -v
 """
 import json
-import os
-import tempfile
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 from sqlalchemy import create_engine, event
diff --git a/backend/tests/test_state_revert.py b/backend/tests/test_state_revert.py
index 9fe18aa..998241b 100644
--- a/backend/tests/test_state_revert.py
+++ b/backend/tests/test_state_revert.py
@@ -11,17 +11,10 @@ only in their outcome.
 
 Run from the backend dir:  python -m pytest tests/test_state_revert.py -v
 """
-import os
-import tempfile
 
 # Point the app at a throwaway SQLite file before importing anything that
 # binds the engine at import time. `app.database` reads `AIDND_DB_PATH`
 # on import.
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 from fastapi import HTTPException
diff --git a/backend/tests/test_story_tree_baseline.py b/backend/tests/test_story_tree_baseline.py
index 36b7697..f5cf8b5 100644
--- a/backend/tests/test_story_tree_baseline.py
+++ b/backend/tests/test_story_tree_baseline.py
@@ -17,15 +17,6 @@ those subphases, the change is wrong, not the test. SP4 is the first
 subphase allowed to move it, and only for the variant-count semantics
 called out in plan/14.
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
@@ -33,9 +24,10 @@ from fastapi.testclient import TestClient
 from app import auth, limits, models
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts
 from app.routers import adventures
 
+from fakes import ScriptedProvider
+
 # A world-state schema, so the RPG layer is exercised rather than skipped.
 SCHEMA = {"player": {"hp": {"min": 0, "max": 100, "initial": 100}}}
 
@@ -52,27 +44,6 @@ modifier(text);
 OPENING = "You enter a cave."
 
 
-class ScriptedProvider:
-    """Streams the next canned reply each call, so successive turns differ."""
-    last_usage = None
-
-    replies: list = []
-    calls = 0
-    prompts: list = []  # every assembled (system, story) pair
-
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
-        ScriptedProvider.calls += 1
-        ScriptedProvider.prompts.append((parts.system, parts.story))
-        reply = ScriptedProvider.replies[index]
-        if isinstance(reply, Exception):
-            raise reply
-        yield ("text", reply)
-
-
 def _make_world(monkeypatch, *, seeded_actions: int = 0):
     """Create a user, a scenario, and an adventure, with `seeded_actions`
     extra story actions written straight to the database. Paging tests need
diff --git a/backend/tests/test_take_edit.py b/backend/tests/test_take_edit.py
index 5300490..d02c433 100644
--- a/backend/tests/test_take_edit.py
+++ b/backend/tests/test_take_edit.py
@@ -20,15 +20,6 @@ be silently broken.
 
     python -m pytest tests/test_take_edit.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
@@ -36,22 +27,9 @@ from fastapi.testclient import TestClient
 from app import auth, limits, models
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts
 from app.routers import adventures
 
-
-class ScriptedProvider:
-    last_usage = None
-    replies: list = []
-    calls = 0
-
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
-        ScriptedProvider.calls += 1
-        yield ("text", ScriptedProvider.replies[index])
+from fakes import ScriptedProvider
 
 
 @pytest.fixture()
diff --git a/backend/tests/test_take_parentage.py b/backend/tests/test_take_parentage.py
index 47fbe84..0ce72e0 100644
--- a/backend/tests/test_take_parentage.py
+++ b/backend/tests/test_take_parentage.py
@@ -20,14 +20,7 @@ they mean.
     python -m pytest tests/test_take_parentage.py -v
 """
 import json
-import os
-import tempfile
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 from fastapi import Depends
@@ -36,22 +29,9 @@ from fastapi.testclient import TestClient
 from app import attempts, auth, limits, models
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts
 from app.routers import adventures
 
-
-class ScriptedProvider:
-    last_usage = None
-    replies: list = []
-    calls = 0
-
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
-        ScriptedProvider.calls += 1
-        yield ("text", ScriptedProvider.replies[index])
+from fakes import ScriptedProvider
 
 
 @pytest.fixture()
diff --git a/backend/tests/test_take_state.py b/backend/tests/test_take_state.py
index c02e1cb..49429d5 100644
--- a/backend/tests/test_take_state.py
+++ b/backend/tests/test_take_state.py
@@ -15,15 +15,6 @@ the line it was on.
 
     python -m pytest tests/test_take_state.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
@@ -31,9 +22,10 @@ from fastapi.testclient import TestClient
 from app import auth, limits, models
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts
 from app.routers import adventures
 
+from fakes import ScriptedProvider
+
 SCHEMA = {"player": {"hp": {"min": 0, "max": 100, "initial": 100}}}
 
 # Ten gold a turn, every turn. A number that only ever increases makes a
@@ -48,20 +40,6 @@ modifier(text);
 """
 
 
-class ScriptedProvider:
-    last_usage = None
-    replies: list = []
-    calls = 0
-
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
-        ScriptedProvider.calls += 1
-        yield ("text", ScriptedProvider.replies[index])
-
-
 @pytest.fixture()
 def client(monkeypatch):
     Base.metadata.create_all(bind=engine)
diff --git a/backend/tests/test_tree_migration.py b/backend/tests/test_tree_migration.py
index e775b59..05746b8 100644
--- a/backend/tests/test_tree_migration.py
+++ b/backend/tests/test_tree_migration.py
@@ -16,14 +16,7 @@ place, would silently skip the DDL and test only half the change.
     python -m pytest tests/test_tree_migration.py -v
 """
 import json
-import os
-import tempfile
 
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
 
 import pytest
 from fastapi import Depends
diff --git a/backend/tests/test_turn_flow_integration.py b/backend/tests/test_turn_flow_integration.py
index c5745f4..0630065 100644
--- a/backend/tests/test_turn_flow_integration.py
+++ b/backend/tests/test_turn_flow_integration.py
@@ -7,15 +7,6 @@ adventure's stored gold total stays correct across play, undo, and retry.
 
     python -m pytest tests/test_turn_flow_integration.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
@@ -23,9 +14,10 @@ from fastapi.testclient import TestClient
 from app import auth, limits, models
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts
 from app.routers import adventures
 
+from fakes import ScriptedProvider
+
 GOLD_SCRIPT = """
 const modifier = (text) => {
   state.gold = (state.gold || 0) + 10;
@@ -35,14 +27,7 @@ modifier(text);
 """
 
 
-class FakeProvider:
-    """Stand-in for OpenAICompatibleProvider: streams one fixed line, no network."""
-    last_usage = None
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        yield ("text", "The torch flickers as you press onward.")
+AI_REPLY = "The torch flickers as you press onward."
 
 
 @pytest.fixture()
@@ -66,7 +51,8 @@ def client(monkeypatch):
     setup.close()
 
     # Force a real, non-demo turn that uses the fake provider.
-    monkeypatch.setattr(adventures, "OpenAICompatibleProvider", FakeProvider)
+    ScriptedProvider.replies = [AI_REPLY]
+    monkeypatch.setattr(adventures, "OpenAICompatibleProvider", ScriptedProvider)
     monkeypatch.setattr(auth, "resolve_provider_config", lambda s: auth.ProviderConfig(
         "http://fake", "k", "test-model", False))
     monkeypatch.setattr(limits, "rate_limit", lambda *a, **k: None)
diff --git a/backend/tests/test_worldstate_integration.py b/backend/tests/test_worldstate_integration.py
index 87a195f..1054344 100644
--- a/backend/tests/test_worldstate_integration.py
+++ b/backend/tests/test_worldstate_integration.py
@@ -4,15 +4,6 @@ undo rolling the world state back.
 
     python -m pytest tests/test_worldstate_integration.py -v
 """
-import os
-import tempfile
-
-_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_tmp.close()
-os.environ["AIDND_DB_PATH"] = _tmp.name
-os.environ.pop("AIDND_DATABASE_URL", None)
-os.environ.pop("DATABASE_URL", None)
-
 import pytest
 from fastapi import Depends
 from fastapi.testclient import TestClient
@@ -20,9 +11,10 @@ from fastapi.testclient import TestClient
 from app import auth, limits, models
 from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
-from app.providers import PromptParts
 from app.routers import adventures
 
+from fakes import ScriptedProvider
+
 SCHEMA = {
     "player": {"hp": {"min": 0, "max": 100, "initial": 100, "max_delta_per_turn": 30}},
     "npcs": {
@@ -45,15 +37,6 @@ AI_REPLY = (
 )
 
 
-class FakeProvider:
-    last_usage = None
-    def __init__(self, *a, **k):
-        pass
-
-    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
-        yield ("text", AI_REPLY)
-
-
 @pytest.fixture()
 def client(monkeypatch):
     Base.metadata.create_all(bind=engine)
@@ -78,7 +61,8 @@ def client(monkeypatch):
     adv_id, user_id = adv.id, user.id
     setup.close()
 
-    monkeypatch.setattr(adventures, "OpenAICompatibleProvider", FakeProvider)
+    ScriptedProvider.replies = [AI_REPLY]
+    monkeypatch.setattr(adventures, "OpenAICompatibleProvider", ScriptedProvider)
     monkeypatch.setattr(auth, "resolve_provider_config", lambda s: auth.ProviderConfig(
         "http://fake", "k", "test-model", False))
     monkeypatch.setattr(limits, "rate_limit", lambda *a, **k: None)