how-we-build 5 already says that if a document states a rule about the
mesh, it says how the rule is verified — an unenforced rule being
indistinguishable from a wrong one, and costing more because people
believe it. That has never been applied to decisions, and a decision
record states the same kind of claim.
The gap was found by review: the lab reached 2,128 lines with 1,072
untested and no stated rule broken, because there is no testing posture in
how-we-build at all. Every decision the lab embodies was verified by hand
and none of it survives the terminal it ran in — which is
04-ISSUES/005 in miniature, coverage assumed rather than checked.
Rejected a coverage percentage: it measures how much code a test touched,
not whether anything important is defended, and would have been satisfied
by testing the parser harder while the hypervisor integration stayed
unasserted.
Rejected test-driven development as a hard rule, and not because it is
wrong in general. Half this implementation was discovery — that the
hypervisor CLI reads a definition from stdin and hangs, that it assigns a
MAC without recording it, that a stock image's networking flushes a static
address. A test written first against undiscovered behaviour asserts a
guess.
So: structure and logic tested first, behaviour against a real system
tested alongside, mocking the boundary forbidden, and a blocking gate as
the definition of done. A test names the decision it defends, which is what
makes the pairing checkable — a decision without one can be found rather
than noticed.
Stated as proposed rather than adopted: 6 requires review by someone who
is not the proposer. Records 0001-0033 predate it and are not retroactively
invalid, but each should acquire a test or an explicit note that it cannot
have one, and until then the rule is aspirational for them — which is the
state 5 warns about, recorded rather than hidden.
