refactor(tests): per-model fakes, FakeMCP and session mocks come from tests/helpers (#2825, milestone 296 area 1, batch 2)

Second pass over the tests/ ledger after bbee0d0. fake_record(**attrs) is the
one MagicMock-with-real-attributes builder (to_dict mirrors them; the
note-2109 hazard documented once); fake_note/fake_task/fake_snippet/
fake_project/fake_milestone/fake_system/fake_rulebook/fake_topic/fake_rule
carry each model's ordinary defaults on top of it, replacing 14 per-file
factories (two rulebook trios in tool-vs-service wordings, _fake_task, _fake_ms,
_fake_project, _plan_note, _fake_snippet, two _snippet adapters now one-liners
over fake_snippet). FakeMCP replaces the five closure-over-a-list registrar
fakes (+ _Recorder); loc() and design_token_stub() replace the paired _loc /
_token / _T stand-ins; every hand-built async_session mock (9 helper defs and
14 inline copies) now starts from make_mock_session(). Call sites rewritten by
AST with each file's former defaults made explicit, so behaviour is unchanged.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/helpers.py

@@ -6,6 +6,8 @@ them; a module imports what it needs with ``from tests.helpers import ...``.
 """
 from __future__ import annotations
 
+from datetime import datetime, timezone
+from types import SimpleNamespace
 from unittest.mock import AsyncMock, MagicMock
 
 
@@ -48,30 +50,135 @@ async def ensure_user(session, username: str, role: str = "user"):
     return user
 
 
-def fake_note(**attrs) -> MagicMock:
-    """A MagicMock note with REAL values on every attribute the product reads
-    to label, scope, or render a record.
+def fake_record(**attrs) -> MagicMock:
+    """A MagicMock record with REAL values on the attributes named, and a
+    ``to_dict()`` that mirrors them.
 
     The hazard this exists for (note 2109): an auto-created MagicMock attribute
-    is truthy and has a repr. The injected menu reads ``is_task`` /
-    ``task_kind`` / ``note_type`` for its kind marker, ``user_id`` to decide
-    whether a line needs a "shared by …" attribution, ``data`` for a snippet's
-    language tag, and ``deleted_at`` to spot trash — on a bare MagicMock every
-    record renders as another user's trashed task with a mock repr for a
-    language. Defaults below are the ORDINARY state (own note, live, no
-    structured data); override what the test is about.
-
-    ``to_dict()`` returns the same values as a plain dict, so a tool that
-    repackages ``note.to_dict()`` sees keys that agree with the attributes.
+    is truthy and has a repr — so a bare MagicMock handed to the product reads
+    as trashed, shared, a task, and owned by a MagicMock. Name every attribute
+    the code under test will read; the per-model ``fake_*`` builders below
+    carry the ordinary defaults so a call site states only what the test is
+    about. ``created_at`` / ``updated_at`` are set as attributes but kept out
+    of ``to_dict()`` (no test serialises them, and the real models isoformat
+    them).
     """
-    values = {
+    n = MagicMock()
+    for key, value in attrs.items():
+        setattr(n, key, value)
+    n.to_dict.return_value = {
+        k: v for k, v in attrs.items() if k not in ("created_at", "updated_at")
+    }
+    return n
+
+
+def _with_defaults(defaults: dict, attrs: dict) -> MagicMock:
+    values = dict(defaults)
+    values.update(attrs)
+    return fake_record(**values)
+
+
+def _now():
+    return datetime.now(timezone.utc)
+
+
+def fake_note(**attrs) -> MagicMock:
+    """A stand-in Note: own (user_id=7, the caller `_bind_user` binds), live,
+    not a task, no structured data. The injected menu reads is_task /
+    task_kind / note_type for its kind marker, user_id for the "shared by …"
+    attribution, data for a snippet's language, deleted_at for trash."""
+    return _with_defaults({
         "id": 1, "title": "t", "body": "", "tags": [], "user_id": 7,
         "note_type": "note", "is_task": False, "task_kind": "work",
         "data": None, "deleted_at": None,
-    }
-    values.update(attrs)
-    n = MagicMock()
-    for key, value in values.items():
-        setattr(n, key, value)
-    n.to_dict.return_value = dict(values)
-    return n
+    }, attrs)
+
+
+def fake_task(**attrs) -> MagicMock:
+    """A stand-in task note — get_task reads parent_id, deleted_at, user_id."""
+    return _with_defaults({
+        "id": 1, "title": "t", "body": "", "status": "todo", "priority": "none",
+        "tags": [], "parent_id": None, "project_id": None, "is_task": True,
+        "task_kind": "work", "user_id": 7, "deleted_at": None,
+    }, attrs)
+
+
+def fake_snippet(**attrs) -> MagicMock:
+    """A stand-in snippet note. ``data`` is explicitly None: snippet_fields
+    prefers `data` when truthy, and a MagicMock is truthy."""
+    return _with_defaults({
+        "id": 1, "title": "debounce — rate-limit a callback",
+        "body": "```js\nreturn 1\n```\n", "tags": ["js", "snippet"],
+        "note_type": "snippet", "is_task": False, "task_kind": "work",
+        "user_id": 7, "data": None, "deleted_at": None,
+    }, attrs)
+
+
+def fake_project(**attrs) -> MagicMock:
+    """design_system_id is explicit: a truthy auto-attribute would route every
+    project through the design-system branch and out to a real database."""
+    return _with_defaults({
+        "id": 1, "title": "P", "description": "", "goal": "", "status": "active",
+        "color": None, "design_system_id": None, "user_id": 7,
+    }, attrs)
+
+
+def fake_milestone(**attrs) -> MagicMock:
+    return _with_defaults({
+        "id": 1, "project_id": 1, "title": "MS", "description": None,
+        "status": "active", "order_index": 0,
+    }, attrs)
+
+
+def fake_system(**attrs) -> MagicMock:
+    return _with_defaults({"id": 1, "name": "Reader", "project_id": 5}, attrs)
+
+
+def fake_rulebook(**attrs) -> MagicMock:
+    return _with_defaults({
+        "id": 1, "owner_user_id": 7, "title": "FabledSword family",
+        "description": "", "created_at": _now(), "updated_at": _now(),
+    }, attrs)
+
+
+def fake_topic(**attrs) -> MagicMock:
+    return _with_defaults({
+        "id": 10, "rulebook_id": 1, "title": "git-workflow", "description": "",
+        "order_index": 0, "created_at": _now(), "updated_at": _now(),
+    }, attrs)
+
+
+def fake_rule(**attrs) -> MagicMock:
+    return _with_defaults({
+        "id": 1, "topic_id": 10, "title": "dev is home",
+        "statement": "Work directly on dev", "why": "", "how_to_apply": "",
+        "order_index": 0, "created_at": _now(), "updated_at": _now(),
+    }, attrs)
+
+
+class FakeMCP:
+    """Stand-in for the FastMCP server a tool module's ``register(mcp)`` is
+    handed: records the ``name=`` of every ``@mcp.tool(...)`` registration in
+    ``names`` and leaves the function untouched, so a test can assert which
+    tools a module exposes."""
+
+    def __init__(self) -> None:
+        self.names: list[str] = []
+
+    def tool(self, name=None):
+        self.names.append(name)
+        return lambda fn: fn
+
+
+def loc(path: str = "", repo: str = "", symbol: str = "") -> dict:
+    """One snippet location, in the shape the record stores."""
+    return {"repo": repo, "path": path, "symbol": symbol}
+
+
+def design_token_stub(name, value_by_mode, group_name=None, purpose=None,
+                      order_index=0, supersedes=None) -> SimpleNamespace:
+    """A design-token row as the cascade / stylesheet code reads it."""
+    return SimpleNamespace(
+        name=name, value_by_mode=value_by_mode, group_name=group_name,
+        purpose=purpose, order_index=order_index, supersedes=supersedes or [],
+    )