tool-mock/docs/GUIDELINES.md

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guidelines

Mock and fixture guidelines

1. Fixtures publish the real contract

• A fixture emits the real topic with the real payload schema. yukart/gnss/fix from a replayed track must be indistinguishable, at the bus, from a real fix.
• ⚠ A fixture that invents its own topic or shape defers integration rather than removing it — the mismatch surfaces when the real source arrives, which is the moment it is most expensive.

2. Do not reimplement our own services

• Stub the car and the hardware. Never write a separate implementation of svc-gw, svc-nav or anything else we wrote — a second implementation of our own contract will drift from the first.
• A service mocking itself, behind its own input interface, is the right shape: one codebase, one contract implementation, a swappable data source. That belongs in the service's own repo, not here.
• None of our services touch hardware, so they all run on x86 unmodified either way.

3. Prefer upstream tools, wrap rather than rewrite

• vcan, canplayer and ICSim already solve the CAN problem. This repo holds the scripts that drive them, not reimplementations of them.

4. Recorded logs are data, not source

• candump logs and GPX tracks are artifacts. Reference them, do not commit them.

5. To be added