TudorandClaude Opus 5
7424cef7c6
Unleash holds flag state; it does not hold the list of flags. REGISTRY is that list, because the SDK evaluates an unknown flag to False and without a registry that is an undeclared False — indistinguishable from a typo in a flag name. Fail-closed throughout, and never raises: an unset UNLEASH_URL, an unreachable server, a client that throws, an undeclared name — all False. A flag layer that can 500 a request path or stop the API booting is worse than one that is switched off. Every flag defaults to False, with no per-flag override, because a flag that defaults on is a kill switch and this is deliberately not one. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015mWQnpye9F299NVRCCSRvj
75 lines
2.7 KiB
Python
75 lines
2.7 KiB
Python
"""Tests for the feature flag layer (spec 2026-08-23).
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None of these need a running Unleash. That is the point: an unset UNLEASH_URL
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means every flag is False, which is what local development and CI get.
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"""
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from datetime import date, timedelta
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from backend import flags
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def test_every_declared_flag_is_keyed_by_its_own_name():
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# One string is the registry key, the Unleash flag name and the JSON key.
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# A mismatch here would mean the UI toggles a flag the code never reads.
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for key, flag in flags.REGISTRY.items():
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assert key == flag.name
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def test_flag_names_are_snake_case():
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# Matches the API's existing convention (admission_distance,
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# rwm_expected_pct) so no case transformation exists to get wrong.
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for name in flags.REGISTRY:
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assert name == name.lower()
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assert "-" not in name and " " not in name
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def test_an_unconfigured_client_evaluates_every_flag_false(monkeypatch):
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monkeypatch.setattr(flags, "_client", None)
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for name in flags.REGISTRY:
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assert flags.is_enabled(name) is False
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def test_an_undeclared_flag_is_false_rather_than_an_error(monkeypatch):
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# A typo'd flag name must not raise in a request path. It is logged as an
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# error, because an undeclared flag is always a bug.
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monkeypatch.setattr(flags, "_client", None)
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assert flags.is_enabled("no_such_flag") is False
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def test_an_exploding_client_is_false_rather_than_a_500(monkeypatch):
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class Boom:
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def is_enabled(self, *a, **kw):
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raise RuntimeError("unleash is on fire")
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monkeypatch.setattr(flags, "_client", Boom())
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name = next(iter(flags.REGISTRY))
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assert flags.is_enabled(name) is False
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def test_all_flags_reports_every_declared_flag(monkeypatch):
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monkeypatch.setattr(flags, "_client", None)
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assert set(flags.all_flags()) == set(flags.REGISTRY)
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assert all(v is False for v in flags.all_flags().values())
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def test_a_flag_older_than_the_limit_fails_this_test():
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"""A tripwire, not an assertion about correctness.
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Flags are temporary scaffolding and the failure mode of every flag system
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is accumulation. This fails on the day a flag turns 90, on whatever PR
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happens to be open — which is the point: someone has to decide.
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To fix: delete the flag and the branches that read it, or, if it genuinely
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still needs to exist, move its `added` date and say why in the commit.
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"""
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stale = [
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f.name for f in flags.REGISTRY.values()
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if date.today() - f.added > timedelta(days=flags.MAX_FLAG_AGE_DAYS)
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]
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assert not stale, (
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f"Flags older than {flags.MAX_FLAG_AGE_DAYS} days: {stale}. "
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"Remove the flag and the code branches it guards, or move its `added` "
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"date deliberately."
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)
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