tests

Instruction file imported from shifulegend/project-zero (.github/instructions/tests.instructions.md). Copyright stays with the author.

Copilot scoped rules: tests (adapter for docs/ai/engineering-rules.md verification)

• make test builds & runs every tests/*.c under ASan/UBSan, aborting on first failure. The bar is a full green run on gcc and clang.
• Zero structs before partial init in test setup (memset before weights_alloc_pointers; zero feature-selecting fields like VisionProjector.scale_factor).
• Asset/CPU/env-dependent tests must skip gracefully, never hard-fail on a missing optional asset.
• Verify the full CI sequence locally (release+test+debug, gcc+clang); a step only validates what it reaches — expect a cascade when unblocking the first failing test.
• Add a golden-output check for behavior changes (e.g. "capital of France" → "Paris").
• make test builds the library as the debug (ASan/UBSan) variant, so engine code is sanitized too (2026-10-21); it replaces a release ./pz — run make release again before benchmarking. The build stamp also tracks compiler and host ISA, so CPU/compiler changes force a clean rebuild.