jschoubben
8f5b786a6b
Tasks 3.1 and 3.3 of novox/hq ADR 0116. One fixture directory, read by every implementation's own runner rather than copied into each — a fixture copied twice is two fixtures, and two fixtures drift. The README settles what ADR 0074's byte-for-byte can and cannot mean. The envelope is exact: the subject, the required headers, each name and format, because those are what two implementations get wrong invisibly. The body is not: it is the module's payload, and Go sorts a map's keys where JavaScript keeps insertion order, so demanding identical bytes would commit every implementation to a canonical JSON encoder to buy a property the mesh never uses. Said plainly, because read strictly it would have sent somebody writing one.
33 lines
1.7 KiB
Markdown
33 lines
1.7 KiB
Markdown
# Conformance fixtures
|
|
|
|
What two implementations of the mesh's module protocol may not disagree about
|
|
([novox/hq ADR 0074](https://git.novox.be), design 19). A fixture is data, not prose: every
|
|
implementation produces it and consumes it, and an implementation that passes the fixtures for a
|
|
capability **claims** that capability.
|
|
|
|
## What "byte-for-byte" means, and what it cannot
|
|
|
|
ADR 0074 says the fixtures must match byte for byte. Taken literally that is more than the mesh
|
|
needs and more than two languages can give:
|
|
|
|
- **The envelope is exact.** The subject, the set of required headers, each header's name, and
|
|
the format of each value. This is what an implementation can get wrong in a way that makes two
|
|
meshes silently ignore each other, so this is what is pinned.
|
|
- **The body is not.** It is the module's own payload, opaque to the mesh, and its serialisation
|
|
is the language's. Go's `encoding/json` sorts a map's keys; JavaScript's `JSON.stringify` keeps
|
|
insertion order. Demanding identical bytes there would mean committing every implementation to
|
|
a canonical JSON encoder — a large promise, bought for a property the mesh never uses. The
|
|
fixture pins that the body **round-trips**: what goes in comes out equal.
|
|
|
|
So: exact where disagreement is invisible, semantic where it is not. Stated here because
|
|
"byte-for-byte" read strictly would have sent somebody implementing a canonical encoder.
|
|
|
|
## Running them
|
|
|
|
The TypeScript implementation: `node conformance/run.mjs` (against a NATS server; see the file).
|
|
The Go implementations read this directory by sibling path, the way the lab finds its siblings.
|
|
|
|
## Layout
|
|
|
|
events/ one emitted event, and what it must look like on the wire
|