test(manifest): keep the rule-manifest test able to catch a keel init reseed

[eaitbrahim]

What this is now

This PR started life as the deploy/live-rules.json DCA budget_usd 25 -> 50 change, split out of #172. #172 was merged and carried that change in, so the value edit, the executor.py comment and the prose are all on main already. Rebased onto origin/main, what remains is the one thing #172 did not land: repairing the test it silently weakened.

The problem

#172 replaced this assertion in test_committed_manifest_is_valid:

assert dca[0]["params"]["budget_usd"] == "25", "DCA budget must not revert to the default 50"

with a check that the manifest's budget equals config.dca.budget_usd. Checking agreement rather than a literal is the right instinct — a hardcoded number there just re-creates the drift it is meant to catch, one deploy later.

But it lost something. The original assertion guarded a specific, real failure: keel init on a fresh box seeds every rule at candidate from each rule kind's constructor defaults, silently discarding any parameter an operator tuned by hand, on a box that otherwise looks correctly provisioned. Nothing errors.

50 is also Dca.__init__'s constructor default. And deploy/live-rules.json's DCA params are now exactly the four constructor defaults:

param	manifest	Dca.__init__ default
cadence_days	7	7
budget_usd	"50"	Decimal("50")
dip_bonus_pct	"0"	Decimal("0")
lookback_days	90	90

So "manifest agrees with config" is satisfied both by a correctly-provisioned deployment and by one that keel init quietly reseeded. The values cannot tell those two states apart any more.

Why I did not do what was asked literally

The instruction was to assert "the value is not merely the constructor default". That is impossible to satisfy honestly — the operator's intended budget is the constructor default. Any assertion of that form would either be false or would require moving Dca's default away from 50 to suit a test, which changes library semantics for a test's convenience. So the guard is restored a different way.

What the test asserts now

1. Agreement — manifest budget_usd == config.live-sandbox.yaml's dca.budget_usd, parsed from the file, not hardcoded. This is the value the executor actually spends.
2. Not seed-shaped — the DCA rule's status is live, and no rule in the manifest is candidate. This is the only discriminator assertion (1) leaves standing: keel init always seeds at candidate regardless of what the params say.
3. The coincidence is pinned, not assumed — the manifest's DCA params are asserted equal to Dca(product_id=...).describe()["params"]. If the operator ever moves the budget off the default, this is what fails, and its message explains that the failure is good news: assertion (1) has regained the ability to catch a reseed on its own, and (2) is no longer the last line of defence.

Verification

Each assertion was confirmed to fail for the right reason, by mutating the committed manifest and reverting:

• DCA status -> candidate: AssertionError: the live DCA rule is not status=live -- if this is a candidate, keel init likely reseeded it from Dca's constructor defaults...
• budget_usd -> "25": AssertionError: the live DCA rule's budget_usd must match config.dca.budget_usd... assert Decimal('25') == Decimal('50')
• cadence_days -> 14: trips assertion (3) with the "reasoning behind assertion (2) no longer applies" message.

ruff, pytest and mypy clean.

🤖 Generated with Claude Code