ADR 0093: a fixture that runs a module's runtime carries its name; 074 diagnosed, two beds converted; 075 resolved

2026-09-21 19:30:35 +02:00
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+---
+topic: checking it
+status: accepted
+date: 2026-09-21
+deciders: jochen
+reconstructed: false
+extends: 02-DECISIONS/0089-a-bed-reads-the-catalogue-it-proves.md
+---
+
+# 93. A fixture that runs a module's runtime carries the module's name
+
+## Context
+
+[ADR 0089](0089-a-bed-reads-the-catalogue-it-proves.md) said a bed that needs less than a module
+declares is a mesh test, and carries a name of its own. Twelve beds were to be renamed on that
+basis ([issue 074](../04-ISSUES/074-a-mesh-test-wears-a-catalogue-modules-name/00-report.md)).
+Reading how a module's tools are reached showed why they cannot be: the account the mesh issues
+a module is scoped to `serve.<module>.*` from the manifest's name, and the runtime binds its tool
+queues under the name baked into its image. A fixture named otherwise but running the real
+runtime would be refused its own queues. The name is not a label; it is the tool namespace and
+the broker scope.
+
+## Considered Options
+
+1. **Rename anyway, and rebuild each runtime under the fixture's name.** Rejected: a runtime built
+   under a false name proves nothing about the module and costs a build per bed.
+2. **A fixture that runs a module's runtime carries the module's name, and therefore reads the
+   catalogue.** Adopted.
+
+## Decision
+
+A bed that runs a module's runtime installs the catalogue's manifest for that module and what it
+requires — the vault for a `secret`, the route module for a route — and proves the mechanism
+against the real module. A name of its own is for a fixture that runs no real runtime: a
+declaration-only stub, a bare upstream image.
+
+## Consequences
+
+The mechanism beds become module beds with a mechanism inside them, which is more than they
+were. What got harder: a bed that wanted a cut-down redis now raises the vault beside it; one that
+wanted a sidecar without its server raises the server. Each conversion is a lab run, and the beds
+still carrying a copy are declared with this reason until converted.
+
+## How it is checked
+
+The lab's inline-copy check refuses undeclared copies as before; the declared list's reason for
+these beds names this record. Two beds converted with the vault beside them ran green.
+
+## References
+
+- [issue 074](../04-ISSUES/074-a-mesh-test-wears-a-catalogue-modules-name/00-report.md)
+- [ADR 0089](0089-a-bed-reads-the-catalogue-it-proves.md), [ADR 0047](0047-a-module-runs-its-code-as-its-own-process-with-its-own-account.md)
+- [`03-DESIGN/01-to-be/01-end-to-end-testing.md`](../03-DESIGN/01-to-be/01-end-to-end-testing.md)
@@ -165,6 +165,7 @@ python3 00-META/checks/index.py            fail if stale
 - **0017** — [A test defends a decision](0017-a-test-defends-a-decision.md)
 - **0018** — [A picture of a system is read from the system, never from what asked for it](0018-a-picture-is-read-from-what-runs.md)
 - **0089** — [A bed reads the catalogue it proves](0089-a-bed-reads-the-catalogue-it-proves.md)
+- **0093** — [A fixture that runs a module's runtime carries the module's name](0093-a-fixture-that-runs-a-modules-runtime-carries-its-name.md)

 ### How we work