Claude
37b1527279
Captain Bob, 2026-11-12: "Build an appropriate test harness! Love the idea." The kernel had no tests below the boots, so defects QEMU cannot provoke could not be tested first. Plan: docs/v4.0.0/plans/2026-11-12-kernel-host-tests.md. kernel/tests/: one host program per kernel source, built with that source as it is, the kernel's flags (-std=c99 -Wall -Wextra -Werror), and fakes -- the console captured line by line, a deterministic RNG that can fail, and a RAM disk whose reads, writes or flushes fail at chosen 1 KiB blocks. make -C kernel/tests test runs them; SRC_<test>= runs a test against other code, which is how a test is seen to fail against the code before a fix. test_gpt.c, 12 checks: a table written and read back; 16, 17 and 18 used entries against max 16 and an entry out of range after the 16th (#180); the RNG, the first write, a later write and a flush failing (#168). Against gpt.c before #168 and #180: 4 failures, each defect caught. Now: 0. Both runs in logs/.../kernel-tests/. Not yet a protocol stage: to rule (the plan, step 5). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017RzZgrf7V7Zk2iczBXDRbm
2.5 KiB
2.5 KiB
Kernel host tests -- plan and progress (kept current, one line per increment)
Captain Bob, 2026-11-12: "Build an appropriate test harness! Love the idea." -- for the kernel's own
C code, so that a defect QEMU cannot provoke (a USB descriptor no emulated device sends, a write that
fails half-way, a stop that spins) is still tested first and seen to fail. v4 has had this since step
1 (make -C v4 test); the kernel had none.
The design (my calls, open to a ruling)
kernel/tests/, one program per kernel source under test:test_<unit>.ccompiled on the host with the kernel's own source file,-std=c99 -Wall -Wextra -Werror, and nothing else of the kernel.make -C kernel/tests testbuilds and runs them all; each printsN checks, M failuresas v4's do, and the run fails if any does.- Fakes, not mocks (
kernel/tests/fakes.[ch]): the console captured line by line (so a test reads what the kernel said), a deterministic RNG, and a RAM disk whose reads or writes fail at the 1 KiB blocks a test chooses -- the disk faults QEMU's blkdebug gives the boots, here per block and without a boot. - Code is moved only to be testable, never changed in the move. Where a unit is buried in a larger function (the xHCI configuration-descriptor walk inside the event loop), it is moved out into a function of its own in one commit, the boots and the tests unchanged, and then tested.
- Not a substitute for acceptance. The boots stay the only acceptance of the kernel; these run
beside them. Whether they become a stage of the protocol and the PR's gate (
nightly.sh kernel-tests, after test-32) is to rule -- proposed once there are enough tests to matter.
Increments
- 1. The harness (
Makefile,harness.h,fakes.[ch]) andtest_gpt.c:gpt_readandgpt_write_oneagainst a RAM disk -- a valid table; more used entries thanmax(#180); an entry out of range pastmax(#180); the first write failing and a later one failing (#168). Seen to fail againstgpt.cas it was before #168 and #180 (54311be1~1): 12 checks, 4 failures -- each of the two defects caught. Now: 0 failures. - 2. The xHCI configuration-descriptor walk moved out of the event loop, then #170 and #171 tested first and fixed.
- 3. #176 (seeds wiped on every exit), #177 (the fatal stops halt), #178 (the slot array) -- each with what it needs moved or faked.
- 4. #179 once #187 is ruled (the block layer's header read).
- 5. To rule: the kernel tests as a protocol stage and in the gate.