Cost-stratified test tiers: Smoke, Lite, targeted, full.

Test-onion tiers (Smoke / Lite / targeted / full)

Intent — A tiered test suite that stratifies ~4000+ tests by cost and coverage (Smoke, Lite, targeted, full) so cheap tiers gate fast iterations and the full tier gates deploy, pinning behaviour at the right price per decision.

Motivation — the failure it kills

Four thousand-plus tests are too slow to run on every change, but skipping them lets regressions land. Left unstratified you get one of two failures: unusably slow iteration (run everything, always) or missed regressions (run nothing, hope). It recurs on every change and every deploy; the tension is constant.

Why it's not just "run all the tests" (or "run a fixed subset")

Running all 4000 on every iteration is unusable; a fixed subset misses regressions that fall outside it. The onion stratifies by cost matched to the decision being gated: Smoke (~9 tests, <30s) as a deploy pre-gate, Lite (hundreds, single-digit seconds), a targeted ClassName filter (<5s) for the edit loop, and the full tier (~4min) at deploy. One tier for every decision is the failing alternative: it either runs the full suite on every keystroke or gates deploy on the fast subset; each tier sized to its decision avoids both. Escalation rules close the "fixed subset misses things" gap: touching a Runner, Validator, Registry, or a prompt constant forces the full tier before "done."

Mechanism

Trait/filter-based tiers (Suite=Smoke, Suite=Lite, Format=…, FullyQualifiedName~Class). New pre-deploy tests obey the 1-second rule (optimize to <1s or justify in writing) and default to not Lite. The Tier-3 escalation rule names the high-blast-radius surfaces that require the full tier.

Prerequisites

• A trait/filter system on the tests to slice them into tiers.
• Tiers defined by cost + coverage, and a discipline for which tier gates which decision.
• The 1-second rule + escalation rules, or Lite bloats and iteration-tier under-tests.

Consequences & costs

• Tier assignment is judgment. A mis-tiered slow test in Lite erodes the whole tier's speed promise.
• Escalation depends on discipline. The rules only help if agents actually run the full tier when they touch a named surface.
• The full tier is still ~4min — the deliberate price of the deploy gate.

Known uses

• The Suite=Smoke / Suite=Lite / targeted / Format= full tiers.
• The 1-second rule for new pre-deploy tests; the Tier-3 escalation surfaces.

Related mechanisms

• See also (sibling) — property-tests, fuzz-campaigns, ddt-pin-trailers: the other behaviour-pinning bodies in this family.
• Layer — the full tier gates staged-deploy-gates (agent side): the deploy stair runs this suite.