Add CI tests for AMD GPU accelerator detection (real-hardware fixtures)

[hmeiland]

Summary

Adds workflow-based CI tests for AMD GPU accelerator detection in eessi_archdetect.sh, building on the detection logic proposed in #205. All tests use output captured from real hardware (an AMD Radeon Pro V710 / NAVI32, gfx1101), so no AMD GPU is required in CI.

This addresses the AMD-CI gap tracked in #214, complementing the detection work in #205.

What's covered

accelpath()'s AMD path (from #205) has two detection methods; this PR tests both:

• Method 1 — KFD sysfs (/sys/devices/virtual/kfd/kfd/topology/nodes/*/properties, no amd-smi/Python required). This is the path that fires on real AMD hardware where amdgpu-arch isn't in PATH. To make it testable without a GPU, the topology root is made overridable via $EESSI_KFD_TOPOLOGY_ROOT (defaults to the real sysfs path — behavior is unchanged when unset). Fixtures are captured nodes/*/properties files:
  • v710 → node 0 is a CPU node (gfx_target_version 0, must be skipped), node 1 is the GPU (gfx_target_version 110001 → gfx1101). Verifies the gfx_target_version → gfxMAJMINSTEP decode and the CPU-node skip.
  • cpu_only → only a CPU node → no accelerator → exit 2.
• Method 2 — amd-smi fallback: a fake amd-smi on $PATH replays real amd-smi static --asic output (TARGET_GRAPHICS_VERSION: gfx1101), mirroring the existing nvidia-smi test pattern.

Changes

• init/eessi_archdetect.sh: one-line change making the KFD topology root overridable via $EESSI_KFD_TOPOLOGY_ROOT (test seam; default unchanged).
• .github/workflows/tests_archdetect_amd_gpu.yml: new workflow, analogous to tests_archdetect_nvidia_gpu.yml, with kfd_sysfs (v710, cpu_only) and amd_smi (v710) matrices.
• tests/archdetect/kfd/{v710,cpu_only}/: captured KFD topology fixtures + expected output.
• tests/archdetect/amd-smi/: amd-smi stub + expected output.

Verification

Verified locally against the #205 branch, and the gfx1101 result was confirmed on the live V710 (both KFD gfx_target_version=110001 and amd-smi TARGET_GRAPHICS_VERSION: gfx1101 decode to accel/amd/gfx1101):

Scenario	Result
KFD / V710 fixture	accel/amd/gfx1101
KFD / cpu_only	exit 2 (CPU node skipped)
amd-smi stub fallback	accel/amd/gfx1101
NVIDIA cc80 stub (regression)	accel/nvidia/cc80 (unchanged)
No accelerators	exit 2 (unchanged)

Notes

• This depends on the AMD detection logic in Add AMD GPU support to accelpath (WIP) #205; if Add AMD GPU support to accelpath (WIP) #205's approach changes, these fixtures/expected outputs may need adjustment.
• This PR was created with the help of AI (an AI coding assistant / GitHub Copilot).